/contrib/cvs/doc/cvs.texinfo

\input texinfo  @c -*-texinfo-*-
@comment Documentation for CVS.
@setfilename cvs.info
@macro copyleftnotice
@noindent
Copyright @copyright{} 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
                       2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
                       Free Software Foundation, Inc.

@multitable @columnfractions .12 .88
@item Portions
@item @tab Copyright @copyright{} 1999, 2000, 2001, 2002, 2003, 2004, 2005,
				  2006, 2007 Derek R. Price,
@item @tab Copyright @copyright{} 2002, 2003, 2004, 2005, 2006, 2007
                                  Ximbiot @url{http://ximbiot.com},
@item @tab Copyright @copyright{} 1992, 1993, 1999 Signum Support AB,
@item @tab and Copyright @copyright{} others.
@end multitable

@ignore
Permission is granted to process this file through Tex and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by the Free Software Foundation.
@end macro

@comment This file is part of the CVS distribution.

@comment CVS is free software; you can redistribute it and/or modify
@comment it under the terms of the GNU General Public License as published by
@comment the Free Software Foundation; either version 2, or (at your option)
@comment any later version.

@comment CVS is distributed in the hope that it will be useful,
@comment but WITHOUT ANY WARRANTY; without even the implied warranty of
@comment MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
@comment GNU General Public License for more details.

@c See ../README for A4 vs. US letter size.
@c When we provided A4 postscript, and people tried to
@c print it on US letter, the usual complaint was that the
@c page numbers would get cut off.
@c If one prints US letter on A4, reportedly there is
@c some extra space at the top and/or bottom, and the side
@c margins are a bit narrow, but no text is lost.
@c
@c See
@c http://www.ft.uni-erlangen.de/~mskuhn/iso-paper.html
@c for more on paper sizes.  Insuring that margins are
@c big enough to print on either A4 or US letter does
@c indeed seem to be the usual approach (RFC2346).

@c This document seems to get overfull hboxes with some
@c frequency (probably because the tendency is to
@c sanity-check it with "make info" and run TeX less
@c often).  The big ugly boxes just seem to add insult
@c to injury, and I'm not aware of them helping to fix
@c the overfull hboxes at all.
@finalout

@include version.texi
@settitle CVS---Concurrent Versions System v@value{VERSION}
@setchapternewpage odd

@c -- TODO list:
@c -- Fix all lines that match "^@c -- "
@c -- Also places marked with FIXME should be manual
@c problems (as opposed to FIXCVS for CVS problems).

@c @splitrcskeyword{} is used to avoid keyword expansion.  It is replaced by
@c @asis when generating info and dvi, and by <i></i> in the generated html,
@c such that keywords are not expanded in the generated html. 
@ifnothtml
@macro splitrcskeyword {arg}
@asis{}\arg\
@end macro
@end ifnothtml

@ifhtml
@macro splitrcskeyword {arg}
@i{}\arg\
@end macro
@end ifhtml

@dircategory GNU Packages
@direntry
* CVS: (cvs).                   Concurrent Versions System
@end direntry
@dircategory Individual utilities
@direntry
* cvs: (cvs)CVS commands.       Concurrent Versions System
@end direntry

@comment The titlepage section does not appear in the Info file.
@titlepage
@sp 4
@comment The title is printed in a large font.
@center @titlefont{Version Management}
@sp
@center @titlefont{with}
@sp
@center @titlefont{CVS}
@sp 2
@center for @sc{cvs} @value{VERSION}
@comment -release-
@sp 3
@center Per Cederqvist et al

@comment  The following two commands start the copyright page
@comment  for the printed manual.  This will not appear in the Info file.
@page
@vskip 0pt plus 1filll
@copyleftnotice
@end titlepage

@summarycontents

@contents

@comment ================================================================
@comment                   The real text starts here
@comment ================================================================

@ifnottex
@c ---------------------------------------------------------------------
@node    Top
@top

This info manual describes how to use and administer
@sc{cvs} version @value{VERSION}.
@end ifnottex

@ifinfo
@copyleftnotice
@end ifinfo

@c This menu is pretty long.  Not sure how easily that
@c can be fixed (no brilliant ideas right away)...
@menu
* Overview::                    An introduction to CVS
* Repository::                  Where all your sources are stored
* Starting a new project::      Starting a project with CVS
* Revisions::                   Numeric and symbolic names for revisions
* Branching and merging::       Diverging/rejoining branches of development
* Recursive behavior::          CVS descends directories
* Adding and removing::         Adding/removing/renaming files/directories
* History browsing::            Viewing the history of files in various ways

CVS and the Real World.
-----------------------
* Binary files::                CVS can handle binary files
* Multiple developers::         How CVS helps a group of developers
* Revision management::         Policy questions for revision management
* Keyword substitution::        CVS can include the revision inside the file
* Tracking sources::            Tracking third-party sources
* Builds::                      Issues related to CVS and builds
* Special Files::		Devices, links and other non-regular files

References.
-----------
* CVS commands::                CVS commands share some things
* Invoking CVS::                Quick reference to CVS commands
* Administrative files::        Reference manual for the Administrative files
* Environment variables::       All environment variables which affect CVS
* Compatibility::               Upgrading CVS versions
* Troubleshooting::             Some tips when nothing works
* Credits::                     Some of the contributors to this manual
* BUGS::                        Dealing with bugs in CVS or this manual
* Index::                       Index
@end menu

@c ---------------------------------------------------------------------
@node Overview
@chapter Overview
@cindex Overview

This chapter is for people who have never used
@sc{cvs}, and perhaps have never used version control
software before.

If you are already familiar with @sc{cvs} and are just
trying to learn a particular feature or remember a
certain command, you can probably skip everything here.

@menu
* What is CVS?::                What you can do with @sc{cvs}
* What is CVS not?::            Problems @sc{cvs} doesn't try to solve
* A sample session::            A tour of basic @sc{cvs} usage
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node What is CVS?
@section What is CVS?
@cindex What is CVS?
@cindex Introduction to CVS
@cindex CVS, introduction to

@sc{cvs} is a version control system.  Using it, you can
record the history of your source files.

@c -- ///
@c -- ///Those who cannot remember the past are condemned to repeat it.
@c -- ///               -- George Santayana
@c -- //////

@c -- Insert history  quote here!
For example, bugs sometimes creep in when
software is modified, and you might not detect the bug
until a long time after you make the modification.
With @sc{cvs}, you can easily retrieve old versions to see
exactly which change caused the bug.  This can
sometimes be a big help.

You could of course save every version of every file
you have ever created.  This would
however waste an enormous amount of disk space.  @sc{cvs}
stores all the versions of a file in a single file in a
clever way that only stores the differences between
versions.

@sc{cvs} also helps you if you are part of a group of people working
on the same project.  It is all too easy to overwrite
each others' changes unless you are extremely careful.
Some editors, like @sc{gnu} Emacs, try to make sure that
two people never modify the same file at the
same time.  Unfortunately, if someone is using another
editor, that safeguard will not work.  @sc{cvs} solves this problem
by insulating the different developers from each other.  Every
developer works in his own directory, and @sc{cvs} merges
the work when each developer is done.

@cindex History of CVS
@cindex CVS, history of
@cindex Credits (CVS program)
@cindex Contributors (CVS program)
@sc{cvs} started out as a bunch of shell scripts written by
Dick Grune, posted to the newsgroup
@code{comp.sources.unix} in the volume 6
release of July, 1986.  While no actual code from
these shell scripts is present in the current version
of @sc{cvs} much of the @sc{cvs} conflict resolution algorithms
come from them.

In April, 1989, Brian Berliner designed and coded @sc{cvs}.
Jeff Polk later helped Brian with the design of the @sc{cvs}
module and vendor branch support.

@cindex Source, getting CVS source
You can get @sc{cvs} in a variety of ways, including
free download from the Internet.  For more information
on downloading @sc{cvs} and other @sc{cvs} topics, see:

@example
@url{http://cvs.nongnu.org/}
@end example

@cindex Mailing list
@cindex List, mailing list
@cindex Newsgroups
There is a mailing list, known as @email{info-cvs@@nongnu.org},
devoted to @sc{cvs}.  To subscribe or
unsubscribe
write to
@email{info-cvs-request@@nongnu.org}.
If you prefer a Usenet group, there is a one-way mirror (posts to the email
list are usually sent to the news group, but not vice versa) of
@email{info-cvs@@nongnu.org} at @url{news:gnu.cvs.help}.  The right
Usenet group for posts is @url{news:comp.software.config-mgmt} which is for
@sc{cvs} discussions (along with other configuration
management systems).  In the future, it might be
possible to create a
@code{comp.software.config-mgmt.cvs}, but probably only
if there is sufficient @sc{cvs} traffic on
@url{news:comp.software.config-mgmt}.
@c Other random data is that the tale was very
@c skeptical of comp.software.config-mgmt.cvs when the
@c subject came up around 1995 or so (for one
@c thing, because creating it would be a "reorg" which
@c would need to take a more comprehensive look at the
@c whole comp.software.config-mgmt.* hierarchy).

You can also subscribe to the @email{bug-cvs@@nongnu.org} mailing list,
described in more detail in @ref{BUGS}.  To subscribe
send mail to @email{bug-cvs-request@@nongnu.org}.  There is a two-way
Usenet mirror (posts to the Usenet group are usually sent to the email list and
vice versa) of @email{bug-cvs@@nongnu.org} named @url{news:gnu.cvs.bug}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node What is CVS not?
@section What is CVS not?
@cindex What is CVS not?

@sc{cvs} can do a lot of things for you, but it does
not try to be everything for everyone.

@table @asis
@item @sc{cvs} is not a build system.

Though the structure of your repository and modules
file interact with your build system
(e.g. @file{Makefile}s), they are essentially
independent.

@sc{cvs} does not dictate how you build anything.  It
merely stores files for retrieval in a tree structure
you devise.

@sc{cvs} does not dictate how to use disk space in the
checked out working directories.  If you write your
@file{Makefile}s or scripts in every directory so they
have to know the relative positions of everything else,
you wind up requiring the entire repository to be
checked out.

If you modularize your work, and construct a build
system that will share files (via links, mounts,
@code{VPATH} in @file{Makefile}s, etc.), you can
arrange your disk usage however you like.

But you have to remember that @emph{any} such system is
a lot of work to construct and maintain.  @sc{cvs} does
not address the issues involved.

Of course, you should place the tools created to
support such a build system (scripts, @file{Makefile}s,
etc.) under @sc{cvs}.

Figuring out what files need to be rebuilt when
something changes is, again, something to be handled
outside the scope of @sc{cvs}.  One traditional
approach is to use @code{make} for building, and use
some automated tool for generating the dependencies which
@code{make} uses.

See @ref{Builds}, for more information on doing builds
in conjunction with @sc{cvs}.

@item @sc{cvs} is not a substitute for management.

Your managers and project leaders are expected to talk
to you frequently enough to make certain you are aware
of schedules, merge points, branch names and release
dates.  If they don't, @sc{cvs} can't help.

@sc{cvs} is an instrument for making sources dance to
your tune.  But you are the piper and the composer.  No
instrument plays itself or writes its own music.

@item @sc{cvs} is not a substitute for developer communication.

When faced with conflicts within a single file, most
developers manage to resolve them without too much
effort.  But a more general definition of ``conflict''
includes problems too difficult to solve without
communication between developers.

@sc{cvs} cannot determine when simultaneous changes
within a single file, or across a whole collection of
files, will logically conflict with one another.  Its
concept of a @dfn{conflict} is purely textual, arising
when two changes to the same base file are near enough
to spook the merge (i.e., @code{diff3}) command.

@sc{cvs} does not claim to help at all in figuring out
non-textual or distributed conflicts in program logic.

For example: Say you change the arguments to function
@code{X} defined in file @file{A}.  At the same time,
someone edits file @file{B}, adding new calls to
function @code{X} using the old arguments.  You are
outside the realm of @sc{cvs}'s competence.

Acquire the habit of reading specs and talking to your
peers.


@item @sc{cvs} does not have change control

Change control refers to a number of things.  First of
all it can mean @dfn{bug-tracking}, that is being able
to keep a database of reported bugs and the status of
each one (Is it fixed?  In what release?  Has the bug
submitter agreed that it is fixed?).  For interfacing
@sc{cvs} to an external bug-tracking system, see the
@file{rcsinfo} and @file{verifymsg} files
(@pxref{Administrative files}).

Another aspect of change control is keeping track of
the fact that changes to several files were in fact
changed together as one logical change.  If you check
in several files in a single @code{cvs commit}
operation, @sc{cvs} then forgets that those files were
checked in together, and the fact that they have the
same log message is the only thing tying them
together.  Keeping a @sc{gnu} style @file{ChangeLog}
can help somewhat.
@c FIXME: should have an xref to a section which talks
@c more about keeping ChangeLog's with CVS, but that
@c section hasn't been written yet.

Another aspect of change control, in some systems, is
the ability to keep track of the status of each
change.  Some changes have been written by a developer,
others have been reviewed by a second developer, and so
on.  Generally, the way to do this with @sc{cvs} is to
generate a diff (using @code{cvs diff} or @code{diff})
and email it to someone who can then apply it using the
@code{patch} utility.  This is very flexible, but
depends on mechanisms outside @sc{cvs} to make sure
nothing falls through the cracks.

@item @sc{cvs} is not an automated testing program

It should be possible to enforce mandatory use of a
test suite using the @code{commitinfo} file.  I haven't
heard a lot about projects trying to do that or whether
there are subtle gotchas, however.

@item @sc{cvs} does not have a built-in process model

Some systems provide ways to ensure that changes or
releases go through various steps, with various
approvals as needed.  Generally, one can accomplish
this with @sc{cvs} but it might be a little more work.
In some cases you'll want to use the @file{commitinfo},
@file{loginfo}, @file{rcsinfo}, or @file{verifymsg}
files, to require that certain steps be performed
before cvs will allow a checkin.  Also consider whether
features such as branches and tags can be used to
perform tasks such as doing work in a development tree
and then merging certain changes over to a stable tree
only once they have been proven.
@end table

@c ---------------------------------------------------------------------
@node A sample session
@section A sample session
@cindex Example of a work-session
@cindex Getting started
@cindex Work-session, example of
@cindex tc, Trivial Compiler (example)
@cindex Trivial Compiler (example)

@c I think an example is a pretty good way to start.  But
@c somewhere in here, maybe after the sample session,
@c we need something which is kind of
@c a "roadmap" which is more directed at sketching out
@c the functionality of CVS and pointing people to
@c various other parts of the manual.  As it stands now
@c people who read in order get dumped right into all
@c manner of hair regarding remote repositories,
@c creating a repository, etc.
@c
@c The following was in the old Basic concepts node.  I don't
@c know how good a job it does at introducing modules,
@c or whether they need to be introduced so soon, but
@c something of this sort might go into some
@c introductory material somewhere.
@ignore
@cindex Modules (intro)
The repository contains directories and files, in an
arbitrary tree.  The @dfn{modules} feature can be used
to group together a set of directories or files into a
single entity (@pxref{modules}).  A typical usage is to
define one module per project.
@end ignore

As a way of introducing @sc{cvs}, we'll go through a
typical work-session using @sc{cvs}.  The first thing
to understand is that @sc{cvs} stores all files in a
centralized @dfn{repository} (@pxref{Repository}); this
section assumes that a repository is set up.
@c I'm not sure that the sentence concerning the
@c repository quite tells the user what they need to
@c know at this point.  Might need to expand on "centralized"
@c slightly (maybe not here, maybe further down in the example?)

Suppose you are working on a simple compiler.  The source
consists of a handful of C files and a @file{Makefile}.
The compiler is called @samp{tc} (Trivial Compiler),
and the repository is set up so that there is a module
called @samp{tc}.

@menu
* Getting the source::          Creating a workspace
* Committing your changes::     Making your work available to others
* Cleaning up::                 Cleaning up
* Viewing differences::         Viewing differences
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Getting the source
@subsection Getting the source
@cindex Getting the source
@cindex Checking out source
@cindex Fetching source
@cindex Source, getting from CVS
@cindex Checkout, example

The first thing you must do is to get your own working copy of the
source for @samp{tc}.  For this, you use the @code{checkout} command:

@example
$ cvs checkout tc
@end example

@noindent
This will create a new directory called @file{tc} and populate it with
the source files.

@example
$ cd tc
$ ls
CVS         Makefile    backend.c   driver.c    frontend.c  parser.c
@end example

The @file{CVS} directory is used internally by
@sc{cvs}.  Normally, you should not modify or remove
any of the files in it.

You start your favorite editor, hack away at @file{backend.c}, and a couple
of hours later you have added an optimization pass to the compiler.
A note to @sc{rcs} and @sc{sccs} users: There is no need to lock the files that
you want to edit.  @xref{Multiple developers}, for an explanation.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Committing your changes
@subsection Committing your changes
@cindex Committing changes to files
@cindex Log message entry

When you have checked that the compiler is still compilable you decide
to make a new version of @file{backend.c}.  This will
store your new @file{backend.c} in the repository and
make it available to anyone else who is using that same
repository.

@example
$ cvs commit backend.c
@end example

@noindent
@sc{cvs} starts an editor, to allow you to enter a log
message.  You type in ``Added an optimization pass.'',
save the temporary file, and exit the editor.

@cindex CVSEDITOR, environment variable
@cindex EDITOR, environment variable
The environment variable @code{$CVSEDITOR} determines
which editor is started.  If @code{$CVSEDITOR} is not
set, then if the environment variable @code{$EDITOR} is
set, it will be used. If both @code{$CVSEDITOR} and
@code{$EDITOR} are not set then there is a default
which will vary with your operating system, for example
@code{vi} for unix or @code{notepad} for Windows
NT/95.

@cindex VISUAL, environment variable
In addition, @sc{cvs} checks the @code{$VISUAL} environment
variable.  Opinions vary on whether this behavior is desirable and
whether future releases of @sc{cvs} should check @code{$VISUAL} or
ignore it.  You will be OK either way if you make sure that
@code{$VISUAL} is either unset or set to the same thing as
@code{$EDITOR}.

@c This probably should go into some new node
@c containing detailed info on the editor, rather than
@c the intro.  In fact, perhaps some of the stuff with
@c CVSEDITOR and -m and so on should too.
When @sc{cvs} starts the editor, it includes a list of
files which are modified.  For the @sc{cvs} client,
this list is based on comparing the modification time
of the file against the modification time that the file
had when it was last gotten or updated.  Therefore, if
a file's modification time has changed but its contents
have not, it will show up as modified.  The simplest
way to handle this is simply not to worry about it---if
you proceed with the commit @sc{cvs} will detect that
the contents are not modified and treat it as an
unmodified file.  The next @code{update} will clue
@sc{cvs} in to the fact that the file is unmodified,
and it will reset its stored timestamp so that the file
will not show up in future editor sessions.
@c FIXCVS: Might be nice if "commit" and other commands
@c would reset that timestamp too, but currently commit
@c doesn't.
@c FIXME: Need to talk more about the process of
@c prompting for the log message.  Like show an example
@c of what it pops up in the editor, for example.  Also
@c a discussion of how to get the "a)bort, c)ontinue,
@c e)dit" prompt and what to do with it.  Might also
@c work in the suggestion that if you want a diff, you
@c should make it before running commit (someone
@c suggested that the diff pop up in the editor.  I'm
@c not sure that is better than telling people to run
@c "cvs diff" first if that is what they want, but if
@c we want to tell people that, the manual possibly
@c should say it).

If you want to avoid
starting an editor you can specify the log message on
the command line using the @samp{-m} flag instead, like
this:

@example
$ cvs commit -m "Added an optimization pass" backend.c
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Cleaning up
@subsection Cleaning up
@cindex Cleaning up
@cindex Working copy, removing
@cindex Removing your working copy
@cindex Releasing your working copy

Before you turn to other tasks you decide to remove your working copy of
tc.  One acceptable way to do that is of course

@example
$ cd ..
$ rm -r tc
@end example

@noindent
but a better way is to use the @code{release} command (@pxref{release}):

@example
$ cd ..
$ cvs release -d tc
M driver.c
? tc
You have [1] altered files in this repository.
Are you sure you want to release (and delete) directory `tc': n
** `release' aborted by user choice.
@end example

The @code{release} command checks that all your modifications have been
committed.  If history logging is enabled it also makes a note in the
history file.  @xref{history file}.

When you use the @samp{-d} flag with @code{release}, it
also removes your working copy.

In the example above, the @code{release} command wrote a couple of lines
of output.  @samp{? tc} means that the file @file{tc} is unknown to @sc{cvs}.
That is nothing to worry about: @file{tc} is the executable compiler,
and it should not be stored in the repository.  @xref{cvsignore},
for information about how to make that warning go away.
@xref{release output}, for a complete explanation of
all possible output from @code{release}.

@samp{M driver.c} is more serious.  It means that the
file @file{driver.c} has been modified since it was
checked out.

The @code{release} command always finishes by telling
you how many modified files you have in your working
copy of the sources, and then asks you for confirmation
before deleting any files or making any note in the
history file.

You decide to play it safe and answer @kbd{n @key{RET}}
when @code{release} asks for confirmation.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Viewing differences
@subsection Viewing differences
@cindex Viewing differences
@cindex Diff

You do not remember modifying @file{driver.c}, so you want to see what
has happened to that file.

@example
$ cd tc
$ cvs diff driver.c
@end example

This command runs @code{diff} to compare the version of @file{driver.c}
that you checked out with your working copy.  When you see the output
you remember that you added a command line option that enabled the
optimization pass.  You check it in, and release the module.
@c FIXME: we haven't yet defined the term "check in".

@example
$ cvs commit -m "Added an optimization pass" driver.c
Checking in driver.c;
/usr/local/cvsroot/tc/driver.c,v  <--  driver.c
new revision: 1.2; previous revision: 1.1
done
$ cd ..
$ cvs release -d tc
? tc
You have [0] altered files in this repository.
Are you sure you want to release (and delete) directory `tc': y
@end example

@c ---------------------------------------------------------------------
@node Repository
@chapter The Repository
@cindex Repository (intro)
@cindex Repository, example
@cindex Layout of repository
@cindex Typical repository
@cindex /usr/local/cvsroot, as example repository
@cindex cvsroot

The @sc{cvs} @dfn{repository} stores a complete copy of
all the files and directories which are under version
control.

Normally, you never access any of the files in the
repository directly.  Instead, you use @sc{cvs}
commands to get your own copy of the files into a
@dfn{working directory}, and then
work on that copy.  When you've finished a set of
changes, you check (or @dfn{commit}) them back into the
repository.  The repository then contains the changes
which you have made, as well as recording exactly what
you changed, when you changed it, and other such
information.  Note that the repository is not a
subdirectory of the working directory, or vice versa;
they should be in separate locations.
@c Need some example, e.g. repository
@c /usr/local/cvsroot; working directory
@c /home/joe/sources.  But this node is too long
@c as it is; need a little reorganization...

@cindex :local:, setting up
@sc{cvs} can access a repository by a variety of
means.  It might be on the local computer, or it might
be on a computer across the room or across the world.
To distinguish various ways to access a repository, the
repository name can start with an @dfn{access method}.
For example, the access method @code{:local:} means to
access a repository directory, so the repository
@code{:local:/usr/local/cvsroot} means that the
repository is in @file{/usr/local/cvsroot} on the
computer running @sc{cvs}.  For information on other
access methods, see @ref{Remote repositories}.

@c Can se say this more concisely?  Like by passing
@c more of the buck to the Remote repositories node?
If the access method is omitted, then if the repository
starts with @samp{/}, then @code{:local:} is
assumed.  If it does not start with @samp{/} then either
@code{:ext:} or @code{:server:} is assumed.  For
example, if you have a local repository in
@file{/usr/local/cvsroot}, you can use
@code{/usr/local/cvsroot} instead of
@code{:local:/usr/local/cvsroot}.  But if (under
Windows NT, for example) your local repository is
@file{c:\src\cvsroot}, then you must specify the access
method, as in @code{:local:c:/src/cvsroot}.

@c This might appear to go in Repository storage, but
@c actually it is describing something which is quite
@c user-visible, when you do a "cvs co CVSROOT".  This
@c isn't necessary the perfect place for that, though.
The repository is split in two parts.  @file{$CVSROOT/CVSROOT} contains
administrative files for @sc{cvs}.  The other directories contain the actual
user-defined modules.

@menu
* Specifying a repository::     Telling CVS where your repository is
* Repository storage::          The structure of the repository
* Working directory storage::   The structure of working directories
* Intro administrative files::  Defining modules
* Multiple repositories::       Multiple repositories
* Creating a repository::       Creating a repository
* Backing up::                  Backing up a repository
* Moving a repository::         Moving a repository
* Remote repositories::         Accessing repositories on remote machines
* Read-only access::            Granting read-only access to the repository
* Server temporary directory::  The server creates temporary directories
@end menu

@node Specifying a repository
@section Telling CVS where your repository is

There are several ways to tell @sc{cvs}
where to find the repository.  You can name the
repository on the command line explicitly, with the
@code{-d} (for "directory") option:

@example
cvs -d /usr/local/cvsroot checkout yoyodyne/tc
@end example

@cindex .profile, setting CVSROOT in
@cindex .cshrc, setting CVSROOT in
@cindex .tcshrc, setting CVSROOT in
@cindex .bashrc, setting CVSROOT in
@cindex CVSROOT, environment variable
        Or you can set the @code{$CVSROOT} environment
variable to an absolute path to the root of the
repository, @file{/usr/local/cvsroot} in this example.
To set @code{$CVSROOT}, @code{csh} and @code{tcsh}
users should have this line in their @file{.cshrc} or
@file{.tcshrc} files:

@example
setenv CVSROOT /usr/local/cvsroot
@end example

@noindent
@code{sh} and @code{bash} users should instead have these lines in their
@file{.profile} or @file{.bashrc}:

@example
CVSROOT=/usr/local/cvsroot
export CVSROOT
@end example

@cindex Root file, in CVS directory
@cindex CVS/Root file
        A repository specified with @code{-d} will
override the @code{$CVSROOT} environment variable.
Once you've checked a working copy out from the
repository, it will remember where its repository is
(the information is recorded in the
@file{CVS/Root} file in the working copy).

The @code{-d} option and the @file{CVS/Root} file both
override the @code{$CVSROOT} environment variable.  If
@code{-d} option differs from @file{CVS/Root}, the
former is used.  Of course, for proper operation they
should be two ways of referring to the same repository.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Repository storage
@section How data is stored in the repository
@cindex Repository, how data is stored

For most purposes it isn't important @emph{how}
@sc{cvs} stores information in the repository.  In
fact, the format has changed in the past, and is likely
to change in the future.  Since in almost all cases one
accesses the repository via @sc{cvs} commands, such
changes need not be disruptive.

However, in some cases it may be necessary to
understand how @sc{cvs} stores data in the repository,
for example you might need to track down @sc{cvs} locks
(@pxref{Concurrency}) or you might need to deal with
the file permissions appropriate for the repository.

@menu
* Repository files::            What files are stored in the repository
* File permissions::            File permissions
* Windows permissions::         Issues specific to Windows
* Attic::                       Some files are stored in the Attic
* CVS in repository::           Additional information in CVS directory
* Locks::                       CVS locks control concurrent accesses
* CVSROOT storage::             A few things about CVSROOT are different
@end menu

@node Repository files
@subsection Where files are stored within the repository

@c @cindex Filenames, legal
@c @cindex Legal filenames
@c Somewhere we need to say something about legitimate
@c characters in filenames in working directory and
@c repository.  Not "/" (not even on non-unix).  And
@c here is a specific set of issues:
@c 	Files starting with a - are handled inconsistently. They can not
@c   be added to a repository with an add command, because it they are
@c   interpreted as a switch. They can appear in a repository if they are
@c   part of a tree that is imported. They can not be removed from the tree
@c   once they are there.
@c Note that "--" *is* supported (as a
@c consequence of using GNU getopt).  Should document
@c this somewhere ("Common options"?).  The other usual technique,
@c "./-foo", isn't as effective, at least for "cvs add"
@c which doesn't support pathnames containing "/".

The overall structure of the repository is a directory
tree corresponding to the directories in the working
directory.  For example, supposing the repository is in

@example
/usr/local/cvsroot
@end example

@noindent
here is a possible directory tree (showing only the
directories):

@example
@t{/usr}
 |
 +--@t{local}
 |   |
 |   +--@t{cvsroot}
 |   |    |
 |   |    +--@t{CVSROOT}
          |      (administrative files)
          |
          +--@t{gnu}
          |   |
          |   +--@t{diff}
          |   |   (source code to @sc{gnu} diff)
          |   |
          |   +--@t{rcs}
          |   |   (source code to @sc{rcs})
          |   |
          |   +--@t{cvs}
          |       (source code to @sc{cvs})
          |
          +--@t{yoyodyne}
              |
              +--@t{tc}
              |    |
              |    +--@t{man}
              |    |
              |    +--@t{testing}
              |
              +--(other Yoyodyne software)
@end example

With the directories are @dfn{history files} for each file
under version control.  The name of the history file is
the name of the corresponding file with @samp{,v}
appended to the end.  Here is what the repository for
the @file{yoyodyne/tc} directory might look like:
@c FIXME: Should also mention CVS (CVSREP)
@c FIXME? Should we introduce Attic with an xref to
@c Attic?  Not sure whether that is a good idea or not.
@example
  @code{$CVSROOT}
    |
    +--@t{yoyodyne}
    |   |
    |   +--@t{tc}
    |   |   |
            +--@t{Makefile,v}
            +--@t{backend.c,v}
            +--@t{driver.c,v}
            +--@t{frontend.c,v}
            +--@t{parser.c,v}
            +--@t{man}
            |    |
            |    +--@t{tc.1,v}
            |
            +--@t{testing}
                 |
                 +--@t{testpgm.t,v}
                 +--@t{test2.t,v}
@end example

@cindex History files
@cindex RCS history files
@c The first sentence, about what history files
@c contain, is kind of redundant with our intro to what the
@c repository does in node Repository....
The history files contain, among other things, enough
information to recreate any revision of the file, a log
of all commit messages and the user-name of the person
who committed the revision.  The history files are
known as @dfn{RCS files}, because the first program to
store files in that format was a version control system
known as @sc{rcs}.  For a full
description of the file format, see the @code{man} page
@cite{rcsfile(5)}, distributed with @sc{rcs}, or the
file @file{doc/RCSFILES} in the @sc{cvs} source
distribution.  This
file format has become very common---many systems other
than @sc{cvs} or @sc{rcs} can at least import history
files in this format.
@c FIXME: Think about including documentation for this
@c rather than citing it?  In the long run, getting
@c this to be a standard (not sure if we can cope with
@c a standards process as formal as IEEE/ANSI/ISO/etc,
@c though...) is the way to go, so maybe citing is
@c better.

The @sc{rcs} files used in @sc{cvs} differ in a few
ways from the standard format.  The biggest difference
is magic branches; for more information see @ref{Magic
branch numbers}.  Also in @sc{cvs} the valid tag names
are a subset of what @sc{rcs} accepts; for @sc{cvs}'s
rules see @ref{Tags}.

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node File permissions
@subsection File permissions
@c -- Move this to @node Creating a repository or similar
@cindex Security, file permissions in repository
@cindex File permissions, general
@cindex Permissions, general
@c FIXME: we need to somehow reflect "permissions in
@c repository" versus "permissions in working
@c directory" in the index entries.
@cindex Group, UNIX file permissions, in repository
@cindex Read-only files, in repository
All @samp{,v} files are created read-only, and you
should not change the permission of those files.  The
directories inside the repository should be writable by
the persons that have permission to modify the files in
each directory.  This normally means that you must
create a UNIX group (see group(5)) consisting of the
persons that are to edit the files in a project, and
set up the repository so that it is that group that
owns the directory.
(On some systems, you also need to set the set-group-ID-on-execution bit
on the repository directories (see chmod(1)) so that newly-created files
and directories get the group-ID of the parent directory rather than
that of the current process.)

@c See also comment in commitinfo node regarding cases
@c which are really awkward with unix groups.

This means that you can only control access to files on
a per-directory basis.

Note that users must also have write access to check
out files, because @sc{cvs} needs to create lock files
(@pxref{Concurrency}).  You can use LockDir in CVSROOT/config
to put the lock files somewhere other than in the repository
if you want to allow read-only access to some directories
(@pxref{config}).

@c CVS seems to use CVSUMASK in picking permissions for
@c val-tags, but maybe we should say more about this.
@c Like val-tags gets created by someone who doesn't
@c have CVSUMASK set right?
@cindex CVSROOT/val-tags file, and read-only access to projects
@cindex val-tags file, and read-only access to projects
Also note that users must have write access to the
@file{CVSROOT/val-tags} file.  @sc{cvs} uses it to keep
track of what tags are valid tag names (it is sometimes
updated when tags are used, as well as when they are
created).

Each @sc{rcs} file will be owned by the user who last
checked it in.  This has little significance; what
really matters is who owns the directories.

@cindex CVSUMASK, environment variable
@cindex Umask, for repository files
@sc{cvs} tries to set up reasonable file permissions
for new directories that are added inside the tree, but
you must fix the permissions manually when a new
directory should have different permissions than its
parent directory.  If you set the @code{CVSUMASK}
environment variable, that will control the file
permissions which @sc{cvs} uses in creating directories
and/or files in the repository.  @code{CVSUMASK} does
not affect the file permissions in the working
directory; such files have the permissions which are
typical for newly created files, except that sometimes
@sc{cvs} creates them read-only (see the sections on
watches, @ref{Setting a watch}; -r, @ref{Global
options}; or @code{CVSREAD}, @ref{Environment variables}).
@c FIXME: Need more discussion of which
@c group should own the file in the repository.
@c Include a somewhat detailed example of the usual
@c case where CVSUMASK is 007, the developers are all
@c in a group, and that group owns stuff in the
@c repository.  Need to talk about group ownership of
@c newly-created directories/files (on some unices,
@c such as SunOS4, setting the setgid bit on the
@c directories will make files inherit the directory's
@c group.  On other unices, your mileage may vary.  I
@c can't remember what POSIX says about this, if
@c anything).

Note that using the client/server @sc{cvs}
(@pxref{Remote repositories}), there is no good way to
set @code{CVSUMASK}; the setting on the client machine
has no effect.  If you are connecting with @code{rsh}, you
can set @code{CVSUMASK} in @file{.bashrc} or @file{.cshrc}, as
described in the documentation for your operating
system.  This behavior might change in future versions
of @sc{cvs}; do not rely on the setting of
@code{CVSUMASK} on the client having no effect.
@c FIXME: need to explain what a umask is or cite
@c someplace which does.
@c
@c There is also a larger (largely separate) issue
@c about the meaning of CVSUMASK in a non-unix context.
@c For example, whether there is
@c an equivalent which fits better into other
@c protection schemes like POSIX.6, VMS, &c.
@c
@c FIXME: Need one place which discusses this
@c read-only files thing.  Why would one use -r or
@c CVSREAD?  Why would one use watches?  How do they
@c interact?
@c
@c FIXME: We need to state
@c whether using CVSUMASK removes the need for manually
@c fixing permissions (in fact, if we are going to mention
@c manually fixing permission, we better document a lot
@c better just what we mean by "fix").

Using pserver, you will generally need stricter
permissions on the @sc{cvsroot} directory and
directories above it in the tree; see @ref{Password
authentication security}.

@cindex Setuid
@cindex Setgid
@cindex Security, setuid
@cindex Installed images (VMS)
Some operating systems have features which allow a
particular program to run with the ability to perform
operations which the caller of the program could not.
For example, the set user ID (setuid) or set group ID
(setgid) features of unix or the installed image
feature of VMS.  @sc{cvs} was not written to use such
features and therefore attempting to install @sc{cvs} in
this fashion will provide protection against only
accidental lapses; anyone who is trying to circumvent
the measure will be able to do so, and depending on how
you have set it up may gain access to more than just
@sc{cvs}.  You may wish to instead consider pserver.  It
shares some of the same attributes, in terms of
possibly providing a false sense of security or opening
security holes wider than the ones you are trying to
fix, so read the documentation on pserver security
carefully if you are considering this option
(@ref{Password authentication security}).

@node Windows permissions
@subsection File Permission issues specific to Windows
@cindex Windows, and permissions
@cindex File permissions, Windows-specific
@cindex Permissions, Windows-specific

Some file permission issues are specific to Windows
operating systems (Windows 95, Windows NT, and
presumably future operating systems in this family.
Some of the following might apply to OS/2 but I'm not
sure).

If you are using local @sc{cvs} and the repository is on a
networked file system which is served by the Samba SMB
server, some people have reported problems with
permissions.  Enabling WRITE=YES in the samba
configuration is said to fix/workaround it.
Disclaimer: I haven't investigated enough to know the
implications of enabling that option, nor do I know
whether there is something which @sc{cvs} could be doing
differently in order to avoid the problem.  If you find
something out, please let us know as described in
@ref{BUGS}.

@node Attic
@subsection The attic
@cindex Attic

You will notice that sometimes @sc{cvs} stores an
@sc{rcs} file in the @code{Attic}.  For example, if the
@sc{cvsroot} is @file{/usr/local/cvsroot} and we are
talking about the file @file{backend.c} in the
directory @file{yoyodyne/tc}, then the file normally
would be in

@example
/usr/local/cvsroot/yoyodyne/tc/backend.c,v
@end example

@noindent
but if it goes in the attic, it would be in

@example
/usr/local/cvsroot/yoyodyne/tc/Attic/backend.c,v
@end example

@noindent
@cindex Dead state
instead.  It should not matter from a user point of
view whether a file is in the attic; @sc{cvs} keeps
track of this and looks in the attic when it needs to.
But in case you want to know, the rule is that the RCS
file is stored in the attic if and only if the head
revision on the trunk has state @code{dead}.  A
@code{dead} state means that file has been removed, or
never added, for that revision.  For example, if you
add a file on a branch, it will have a trunk revision
in @code{dead} state, and a branch revision in a
non-@code{dead} state.
@c Probably should have some more concrete examples
@c here, or somewhere (not sure exactly how we should
@c arrange the discussion of the dead state, versus
@c discussion of the attic).

@node CVS in repository
@subsection The CVS directory in the repository
@cindex CVS directory, in repository

The @file{CVS} directory in each repository directory
contains information such as file attributes (in a file
called @file{CVS/fileattr}.  In the
future additional files may be added to this directory,
so implementations should silently ignore additional
files.

This behavior is implemented only by @sc{cvs} 1.7 and
later; for details see @ref{Watches Compatibility}.

The format of the @file{fileattr} file is a series of entries
of the following form (where @samp{@{} and @samp{@}}
means the text between the braces can be repeated zero
or more times):

@var{ent-type} @var{filename} <tab> @var{attrname} = @var{attrval}
  @{; @var{attrname} = @var{attrval}@} <linefeed>

@var{ent-type} is @samp{F} for a file, in which case the entry specifies the
attributes for that file.

@var{ent-type} is @samp{D},
and @var{filename} empty, to specify default attributes
to be used for newly added files.

Other @var{ent-type} are reserved for future expansion.  @sc{cvs} 1.9 and older
will delete them any time it writes file attributes.
@sc{cvs} 1.10 and later will preserve them.

Note that the order of the lines is not significant;
a program writing the fileattr file may
rearrange them at its convenience.

There is currently no way of quoting tabs or line feeds in the
filename, @samp{=} in @var{attrname},
@samp{;} in @var{attrval}, etc.  Note: some implementations also
don't handle a NUL character in any of the fields, but
implementations are encouraged to allow it.

By convention, @var{attrname} starting with @samp{_} is for an attribute given
special meaning by @sc{cvs}; other @var{attrname}s are for user-defined attributes
(or will be, once implementations start supporting user-defined attributes).

Built-in attributes:

@table @code
@item _watched
Present means the file is watched and should be checked out
read-only.

@item _watchers
Users with watches for this file.  Value is
@var{watcher} > @var{type} @{ , @var{watcher} > @var{type} @}
where @var{watcher} is a username, and @var{type}
is zero or more of edit,unedit,commit separated by
@samp{+} (that is, nothing if none; there is no "none" or "all" keyword).

@item _editors
Users editing this file.  Value is
@var{editor} > @var{val} @{ , @var{editor} > @var{val} @}
where @var{editor} is a username, and @var{val} is
@var{time}+@var{hostname}+@var{pathname}, where
@var{time} is when the @code{cvs edit} command (or
equivalent) happened,
and @var{hostname} and @var{pathname} are for the working directory.
@end table

Example:

@c FIXME: sanity.sh should contain a similar test case
@c so we can compare this example from something from
@c Real Life(TM).  See cvsclient.texi (under Notify) for more
@c discussion of the date format of _editors.
@example
Ffile1 _watched=;_watchers=joe>edit,mary>commit
Ffile2 _watched=;_editors=sue>8 Jan 1975+workstn1+/home/sue/cvs
D _watched=
@end example

@noindent
means that the file @file{file1} should be checked out
read-only.  Furthermore, joe is watching for edits and
mary is watching for commits.  The file @file{file2}
should be checked out read-only; sue started editing it
on 8 Jan 1975 in the directory @file{/home/sue/cvs} on
the machine @code{workstn1}.  Future files which are
added should be checked out read-only.  To represent
this example here, we have shown a space after
@samp{D}, @samp{Ffile1}, and @samp{Ffile2}, but in fact
there must be a single tab character there and no spaces.

@node Locks
@subsection CVS locks in the repository

@cindex #cvs.rfl, technical details
@cindex #cvs.wfl, technical details
@cindex #cvs.lock, technical details
@cindex Locks, cvs, technical details
For an introduction to @sc{cvs} locks focusing on
user-visible behavior, see @ref{Concurrency}.  The
following section is aimed at people who are writing
tools which want to access a @sc{cvs} repository without
interfering with other tools accessing the same
repository.  If you find yourself confused by concepts
described here, like @dfn{read lock}, @dfn{write lock},
and @dfn{deadlock}, you might consult the literature on
operating systems or databases.

@cindex #cvs.tfl
Any file in the repository with a name starting
with @file{#cvs.rfl.} is a read lock.  Any file in
the repository with a name starting with
@file{#cvs.wfl} is a write lock.  Old versions of @sc{cvs}
(before @sc{cvs} 1.5) also created files with names starting
with @file{#cvs.tfl}, but they are not discussed here.
The directory @file{#cvs.lock} serves as a master
lock.  That is, one must obtain this lock first before
creating any of the other locks.

To obtain a read lock, first create the @file{#cvs.lock}
directory.  This operation must be atomic (which should
be true for creating a directory under most operating
systems).  If it fails because the directory already
existed, wait for a while and try again.  After
obtaining the @file{#cvs.lock} lock, create a file
whose name is @file{#cvs.rfl.} followed by information
of your choice (for example, hostname and process
identification number).  Then remove the
@file{#cvs.lock} directory to release the master lock.
Then proceed with reading the repository.  When you are
done, remove the @file{#cvs.rfl} file to release the
read lock.

To obtain a write lock, first create the
@file{#cvs.lock} directory, as with read locks.  Then
check that there are no files whose names start with
@file{#cvs.rfl.}.  If there are, remove
@file{#cvs.lock}, wait for a while, and try again.  If
there are no readers, then create a file whose name is
@file{#cvs.wfl} followed by information of your choice
(for example, hostname and process identification
number).  Hang on to the @file{#cvs.lock} lock.  Proceed
with writing the repository.  When you are done, first
remove the @file{#cvs.wfl} file and then the
@file{#cvs.lock} directory. Note that unlike the
@file{#cvs.rfl} file, the @file{#cvs.wfl} file is just
informational; it has no effect on the locking operation
beyond what is provided by holding on to the
@file{#cvs.lock} lock itself.

Note that each lock (write lock or read lock) only locks
a single directory in the repository, including
@file{Attic} and @file{CVS} but not including
subdirectories which represent other directories under
version control.  To lock an entire tree, you need to
lock each directory (note that if you fail to obtain
any lock you need, you must release the whole tree
before waiting and trying again, to avoid deadlocks).

Note also that @sc{cvs} expects write locks to control
access to individual @file{foo,v} files.  @sc{rcs} has
a scheme where the @file{,foo,} file serves as a lock,
but @sc{cvs} does not implement it and so taking out a
@sc{cvs} write lock is recommended.  See the comments at
rcs_internal_lockfile in the @sc{cvs} source code for
further discussion/rationale.

@node CVSROOT storage
@subsection How files are stored in the CVSROOT directory
@cindex CVSROOT, storage of files

The @file{$CVSROOT/CVSROOT} directory contains the
various administrative files.  In some ways this
directory is just like any other directory in the
repository; it contains @sc{rcs} files whose names end
in @samp{,v}, and many of the @sc{cvs} commands operate
on it the same way.  However, there are a few
differences.

For each administrative file, in addition to the
@sc{rcs} file, there is also a checked out copy of the
file.  For example, there is an @sc{rcs} file
@file{loginfo,v} and a file @file{loginfo} which
contains the latest revision contained in
@file{loginfo,v}.  When you check in an administrative
file, @sc{cvs} should print

@example
cvs commit: Rebuilding administrative file database
@end example

@noindent
and update the checked out copy in
@file{$CVSROOT/CVSROOT}.  If it does not, there is
something wrong (@pxref{BUGS}).  To add your own files
to the files to be updated in this fashion, you can add
them to the @file{checkoutlist} administrative file
(@pxref{checkoutlist}).

@cindex modules.db
@cindex modules.pag
@cindex modules.dir
By default, the @file{modules} file behaves as
described above.  If the modules file is very large,
storing it as a flat text file may make looking up
modules slow (I'm not sure whether this is as much of a
concern now as when @sc{cvs} first evolved this
feature; I haven't seen benchmarks).  Therefore, by
making appropriate edits to the @sc{cvs} source code
one can store the modules file in a database which
implements the @code{ndbm} interface, such as Berkeley
db or GDBM.  If this option is in use, then the modules
database will be stored in the files @file{modules.db},
@file{modules.pag}, and/or @file{modules.dir}.
@c I think fileattr also will use the database stuff.
@c Anything else?

For information on the meaning of the various
administrative files, see @ref{Administrative files}.

@node Working directory storage
@section How data is stored in the working directory

@c FIXME: Somewhere we should discuss timestamps (test
@c case "stamps" in sanity.sh).  But not here.  Maybe
@c in some kind of "working directory" chapter which
@c would encompass the "Builds" one?  But I'm not sure
@c whether that is a good organization (is it based on
@c what the user wants to do?).

@cindex CVS directory, in working directory
While we are discussing @sc{cvs} internals which may
become visible from time to time, we might as well talk
about what @sc{cvs} puts in the @file{CVS} directories
in the working directories.  As with the repository,
@sc{cvs} handles this information and one can usually
access it via @sc{cvs} commands.  But in some cases it
may be useful to look at it, and other programs, such
as the @code{jCVS} graphical user interface or the
@code{VC} package for emacs, may need to look at it.
Such programs should follow the recommendations in this
section if they hope to be able to work with other
programs which use those files, including future
versions of the programs just mentioned and the
command-line @sc{cvs} client.

The @file{CVS} directory contains several files.
Programs which are reading this directory should
silently ignore files which are in the directory but
which are not documented here, to allow for future
expansion.

The files are stored according to the text file
convention for the system in question.  This means that
working directories are not portable between systems
with differing conventions for storing text files.
This is intentional, on the theory that the files being
managed by @sc{cvs} probably will not be portable between
such systems either.

@table @file
@item Root
This file contains the current @sc{cvs} root, as
described in @ref{Specifying a repository}.

@cindex Repository file, in CVS directory
@cindex CVS/Repository file
@item Repository
This file contains the directory within the repository
which the current directory corresponds with.  It can
be either an absolute pathname or a relative pathname;
@sc{cvs} has had the ability to read either format
since at least version 1.3 or so.  The relative
pathname is relative to the root, and is the more
sensible approach, but the absolute pathname is quite
common and implementations should accept either.  For
example, after the command

@example
cvs -d :local:/usr/local/cvsroot checkout yoyodyne/tc
@end example

@noindent
@file{Root} will contain

@example
:local:/usr/local/cvsroot
@end example

@noindent
and @file{Repository} will contain either

@example
/usr/local/cvsroot/yoyodyne/tc
@end example

@noindent
or

@example
yoyodyne/tc
@end example

If the particular working directory does not correspond
to a directory in the repository, then @file{Repository}
should contain @file{CVSROOT/Emptydir}.
@cindex Emptydir, in CVSROOT directory
@cindex CVSROOT/Emptydir directory

@cindex Entries file, in CVS directory
@cindex CVS/Entries file
@item Entries
This file lists the files and directories in the
working directory.
The first character of each line indicates what sort of
line it is.  If the character is unrecognized, programs
reading the file should silently skip that line, to
allow for future expansion.

If the first character is @samp{/}, then the format is:

@example
/@var{name}/@var{revision}/@var{timestamp}[+@var{conflict}]/@var{options}/@var{tagdate}
@end example

@noindent
where @samp{[} and @samp{]} are not part of the entry,
but instead indicate that the @samp{+} and conflict
marker are optional.  @var{name} is the name of the
file within the directory.  @var{revision} is the
revision that the file in the working derives from, or
@samp{0} for an added file, or @samp{-} followed by a
revision for a removed file.  @var{timestamp} is the
timestamp of the file at the time that @sc{cvs} created
it; if the timestamp differs with the actual
modification time of the file it means the file has
been modified.  It is stored in
the format used by the ISO C asctime() function (for
example, @samp{Sun Apr  7 01:29:26 1996}).  One may
write a string which is not in that format, for
example, @samp{Result of merge}, to indicate that the
file should always be considered to be modified.  This
is not a special case; to see whether a file is
modified a program should take the timestamp of the file
and simply do a string compare with @var{timestamp}.
If there was a conflict, @var{conflict} can be set to
the modification time of the file after the file has been
written with conflict markers (@pxref{Conflicts example}).
Thus if @var{conflict} is subsequently the same as the actual
modification time of the file it means that the user
has obviously not resolved the conflict.  @var{options}
contains sticky options (for example @samp{-kb} for a
binary file).  @var{tagdate} contains @samp{T} followed
by a tag name, or @samp{D} for a date, followed by a
sticky tag or date.  Note that if @var{timestamp}
contains a pair of timestamps separated by a space,
rather than a single timestamp, you are dealing with a
version of @sc{cvs} earlier than @sc{cvs} 1.5 (not
documented here).

The timezone on the timestamp in CVS/Entries (local or
universal) should be the same as the operating system
stores for the timestamp of the file itself.  For
example, on Unix the file's timestamp is in universal
time (UT), so the timestamp in CVS/Entries should be
too.  On @sc{vms}, the file's timestamp is in local
time, so @sc{cvs} on @sc{vms} should use local time.
This rule is so that files do not appear to be modified
merely because the timezone changed (for example, to or
from summer time).
@c See comments and calls to gmtime() and friends in
@c src/vers_ts.c (function time_stamp).

If the first character of a line in @file{Entries} is
@samp{D}, then it indicates a subdirectory.  @samp{D}
on a line all by itself indicates that the program
which wrote the @file{Entries} file does record
subdirectories (therefore, if there is such a line and
no other lines beginning with @samp{D}, one knows there
are no subdirectories).  Otherwise, the line looks
like:

@example
D/@var{name}/@var{filler1}/@var{filler2}/@var{filler3}/@var{filler4}
@end example

@noindent
where @var{name} is the name of the subdirectory, and
all the @var{filler} fields should be silently ignored,
for future expansion.  Programs which modify
@code{Entries} files should preserve these fields.

The lines in the @file{Entries} file can be in any order.

@cindex Entries.Log file, in CVS directory
@cindex CVS/Entries.Log file
@item Entries.Log
This file does not record any information beyond that
in @file{Entries}, but it does provide a way to update
the information without having to rewrite the entire
@file{Entries} file, including the ability to preserve
the information even if the program writing
@file{Entries} and @file{Entries.Log} abruptly aborts.
Programs which are reading the @file{Entries} file
should also check for @file{Entries.Log}.  If the latter
exists, they should read @file{Entries} and then apply
the changes mentioned in @file{Entries.Log}.  After
applying the changes, the recommended practice is to
rewrite @file{Entries} and then delete @file{Entries.Log}.
The format of a line in @file{Entries.Log} is a single
character command followed by a space followed by a
line in the format specified for a line in
@file{Entries}.  The single character command is
@samp{A} to indicate that the entry is being added,
@samp{R} to indicate that the entry is being removed,
or any other character to indicate that the entire line
in @file{Entries.Log} should be silently ignored (for
future expansion).  If the second character of the line
in @file{Entries.Log} is not a space, then it was
written by an older version of @sc{cvs} (not documented
here).

Programs which are writing rather than reading can
safely ignore @file{Entries.Log} if they so choose.

@cindex Entries.Backup file, in CVS directory
@cindex CVS/Entries.Backup file
@item Entries.Backup
This is a temporary file.  Recommended usage is to
write a new entries file to @file{Entries.Backup}, and
then to rename it (atomically, where possible) to @file{Entries}.

@cindex Entries.Static file, in CVS directory
@cindex CVS/Entries.Static file
@item Entries.Static
The only relevant thing about this file is whether it
exists or not.  If it exists, then it means that only
part of a directory was gotten and @sc{cvs} will
not create additional files in that directory.  To
clear it, use the @code{update} command with the
@samp{-d} option, which will get the additional files
and remove @file{Entries.Static}.
@c FIXME: This needs to be better documented, in places
@c other than Working Directory Storage.
@c FIXCVS: The fact that this setting exists needs to
@c be more visible to the user.  For example "cvs
@c status foo", in the case where the file would be
@c gotten except for Entries.Static, might say
@c something to distinguish this from other cases.
@c One thing that periodically gets suggested is to
@c have "cvs update" print something when it skips
@c files due to Entries.Static, but IMHO that kind of
@c noise pretty much makes the Entries.Static feature
@c useless.

@cindex Tag file, in CVS directory
@cindex CVS/Tag file
@cindex Sticky tags/dates, per-directory
@cindex Per-directory sticky tags/dates
@item Tag
This file contains per-directory sticky tags or dates.
The first character is @samp{T} for a branch tag,
@samp{N} for a non-branch tag, or @samp{D} for a date,
or another character to mean the file should be
silently ignored, for future expansion.  This character
is followed by the tag or date.  Note that
per-directory sticky tags or dates are used for things
like applying to files which are newly added; they
might not be the same as the sticky tags or dates on
individual files.  For general information on sticky
tags and dates, see @ref{Sticky tags}.
@c FIXME: This needs to be much better documented,
@c preferably not in the context of "working directory
@c storage".
@c FIXME: The Sticky tags node needs to discuss, or xref to
@c someplace which discusses, per-directory sticky
@c tags and the distinction with per-file sticky tags.

@cindex Notify file, in CVS directory
@cindex CVS/Notify file
@item Notify
This file stores notifications (for example, for
@code{edit} or @code{unedit}) which have not yet been
sent to the server.  Its format is not yet documented
here.

@cindex Notify.tmp file, in CVS directory
@cindex CVS/Notify.tmp file
@item Notify.tmp
This file is to @file{Notify} as @file{Entries.Backup}
is to @file{Entries}.  That is, to write @file{Notify},
first write the new contents to @file{Notify.tmp} and
then (atomically where possible), rename it to
@file{Notify}.

@cindex Base directory, in CVS directory
@cindex CVS/Base directory
@item Base
If watches are in use, then an @code{edit} command
stores the original copy of the file in the @file{Base}
directory.  This allows the @code{unedit} command to
operate even if it is unable to communicate with the
server.

@cindex Baserev file, in CVS directory
@cindex CVS/Baserev file
@item Baserev
The file lists the revision for each of the files in
the @file{Base} directory.  The format is:

@example
B@var{name}/@var{rev}/@var{expansion}
@end example

@noindent
where @var{expansion} should be ignored, to allow for
future expansion.

@cindex Baserev.tmp file, in CVS directory
@cindex CVS/Baserev.tmp file
@item Baserev.tmp
This file is to @file{Baserev} as @file{Entries.Backup}
is to @file{Entries}.  That is, to write @file{Baserev},
first write the new contents to @file{Baserev.tmp} and
then (atomically where possible), rename it to
@file{Baserev}.

@cindex Template file, in CVS directory
@cindex CVS/Template file
@item Template
This file contains the template specified by the
@file{rcsinfo} file (@pxref{rcsinfo}).  It is only used
by the client; the non-client/server @sc{cvs} consults
@file{rcsinfo} directly.
@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Intro administrative files
@section The administrative files
@cindex Administrative files (intro)
@cindex Modules file
@cindex CVSROOT, module name
@cindex Defining modules (intro)

@c FIXME: this node should be reorganized into "general
@c information about admin files" and put the "editing
@c admin files" stuff up front rather than jumping into
@c the details of modules right away.  Then the
@c Administrative files node can go away, the information
@c on each admin file distributed to a place appropriate
@c to its function, and this node can contain a table
@c listing each file and a @ref to its detailed description.

The directory @file{$CVSROOT/CVSROOT} contains some @dfn{administrative
files}.  @xref{Administrative files}, for a complete description.
You can use @sc{cvs} without any of these files, but
some commands work better when at least the
@file{modules} file is properly set up.

The most important of these files is the @file{modules}
file.  It defines all modules in the repository.  This
is a sample @file{modules} file.

@c FIXME: The CVSROOT line is a goofy example now that
@c mkmodules doesn't exist.
@example
CVSROOT         CVSROOT
modules         CVSROOT modules
cvs             gnu/cvs
rcs             gnu/rcs
diff            gnu/diff
tc              yoyodyne/tc
@end example

The @file{modules} file is line oriented.  In its
simplest form each line contains the name of the
module, whitespace, and the directory where the module
resides.  The directory is a path relative to
@code{$CVSROOT}.  The last four lines in the example
above are examples of such lines.

@c FIXME: might want to introduce the concept of options in modules file
@c (the old example which was here, -i mkmodules, is obsolete).

The line that defines the module called @samp{modules}
uses features that are not explained here.
@xref{modules}, for a full explanation of all the
available features.

@c FIXME: subsection without node is bogus
@subsection Editing administrative files
@cindex Editing administrative files
@cindex Administrative files, editing them

You edit the administrative files in the same way that you would edit
any other module.  Use @samp{cvs checkout CVSROOT} to get a working
copy, edit it, and commit your changes in the normal way.

It is possible to commit an erroneous administrative
file.  You can often fix the error and check in a new
revision, but sometimes a particularly bad error in the
administrative file makes it impossible to commit new
revisions.  If and when this happens, you can correct
the problem by temporarily copying a corrected administrative file
directly into the @code{$CVSROOT/CVSROOT} repository directory,
then committing the same correction via a checkout of the @file{CVSROOT}
module.  It is important that the correction also be made via the
checked out copy, or the next checkout and commit to the
<code>CVSROOT</code> module will overwrite the correction that was
copied directly into the repository, possibly breaking things in such
a way as to prevent commits again.
@c @xref{Bad administrative files} for a hint
@c about how to solve such situations.
@c -- administrative file checking--

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Multiple repositories
@section Multiple repositories
@cindex Multiple repositories
@cindex Repositories, multiple
@cindex Many repositories
@cindex Parallel repositories
@cindex Disjoint repositories
@cindex CVSROOT, multiple repositories

In some situations it is a good idea to have more than
one repository, for instance if you have two
development groups that work on separate projects
without sharing any code.  All you have to do to have
several repositories is to specify the appropriate
repository, using the @code{CVSROOT} environment
variable, the @samp{-d} option to @sc{cvs}, or (once
you have checked out a working directory) by simply
allowing @sc{cvs} to use the repository that was used
to check out the working directory
(@pxref{Specifying a repository}).

The big advantage of having multiple repositories is
that they can reside on different servers.  With @sc{cvs}
version 1.10, a single command cannot recurse into
directories from different repositories.  With development
versions of @sc{cvs}, you can check out code from multiple
servers into your working directory.  @sc{cvs} will
recurse and handle all the details of making
connections to as many server machines as necessary to
perform the requested command.  Here is an example of
how to set up a working directory:

@example
cvs -d server1:/cvs co dir1
cd dir1
cvs -d server2:/root co sdir
cvs update
@end example

The @code{cvs co} commands set up the working
directory, and then the @code{cvs update} command will
contact server2, to update the dir1/sdir subdirectory,
and server1, to update everything else.

@c FIXME: Does the FAQ have more about this?  I have a
@c dim recollection, but I'm too lazy to check right now.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Creating a repository
@section Creating a repository

@cindex Repository, setting up
@cindex Creating a repository
@cindex Setting up a repository

This section describes how to set up a @sc{cvs} repository for any
sort of access method.  After completing the setup described in this
section, you should be able to access your @sc{cvs} repository immediately
via the local access method and several remote access methods.  For
more information on setting up remote access to the repository you create
in this section, please read the section on @xref{Remote repositories}.

To set up a @sc{cvs} repository, first choose the
machine and disk on which you want to store the
revision history of the source files.  CPU and memory
requirements are modest, so most machines should be
adequate.  For details see @ref{Server requirements}.
@c Possible that we should be providing a quick rule of
@c thumb, like the 32M memory for the server.  That
@c might increase the number of people who are happy
@c with the answer, without following the xref.

To estimate disk space
requirements, if you are importing RCS files from
another system, the size of those files is the
approximate initial size of your repository, or if you
are starting without any version history, a rule of
thumb is to allow for the server approximately three
times the size of the code to be under @sc{cvs} for the
repository (you will eventually outgrow this, but not
for a while).  On the machines on which the developers
will be working, you'll want disk space for
approximately one working directory for each developer
(either the entire tree or a portion of it, depending
on what each developer uses).

The repository should be accessible
(directly or via a networked file system) from all
machines which want to use @sc{cvs} in server or local
mode; the client machines need not have any access to
it other than via the @sc{cvs} protocol.  It is not
possible to use @sc{cvs} to read from a repository
which one only has read access to; @sc{cvs} needs to be
able to create lock files (@pxref{Concurrency}).

@cindex init (subcommand)
To create a repository, run the @code{cvs init}
command.  It will set up an empty repository in the
@sc{cvs} root specified in the usual way
(@pxref{Repository}).  For example,

@example
cvs -d /usr/local/cvsroot init
@end example

@code{cvs init} is careful to never overwrite any
existing files in the repository, so no harm is done if
you run @code{cvs init} on an already set-up
repository.

@code{cvs init} will enable history logging; if you
don't want that, remove the history file after running
@code{cvs init}.  @xref{history file}.

@node Backing up
@section Backing up a repository
@cindex Repository, backing up
@cindex Backing up, repository

There is nothing particularly magical about the files
in the repository; for the most part it is possible to
back them up just like any other files.  However, there
are a few issues to consider.

@cindex Locks, cvs, and backups
@cindex #cvs.rfl, and backups
The first is that to be paranoid, one should either not
use @sc{cvs} during the backup, or have the backup
program lock @sc{cvs} while doing the backup.  To not
use @sc{cvs}, you might forbid logins to machines which
can access the repository, turn off your @sc{cvs}
server, or similar mechanisms.  The details would
depend on your operating system and how you have
@sc{cvs} set up.  To lock @sc{cvs}, you would create
@file{#cvs.rfl} locks in each repository directory.
See @ref{Concurrency}, for more on @sc{cvs} locks.
Having said all this, if you just back up without any
of these precautions, the results are unlikely to be
particularly dire.  Restoring from backup, the
repository might be in an inconsistent state, but this
would not be particularly hard to fix manually.

When you restore a repository from backup, assuming
that changes in the repository were made after the time
of the backup, working directories which were not
affected by the failure may refer to revisions which no
longer exist in the repository.  Trying to run @sc{cvs}
in such directories will typically produce an error
message.  One way to get those changes back into the
repository is as follows:

@itemize @bullet
@item
Get a new working directory.

@item
Copy the files from the working directory from before
the failure over to the new working directory (do not
copy the contents of the @file{CVS} directories, of
course).

@item
Working in the new working directory, use commands such
as @code{cvs update} and @code{cvs diff} to figure out
what has changed, and then when you are ready, commit
the changes into the repository.
@end itemize

@node Moving a repository
@section Moving a repository
@cindex Repository, moving
@cindex Moving a repository
@cindex Copying a repository

Just as backing up the files in the repository is
pretty much like backing up any other files, if you
need to move a repository from one place to another it
is also pretty much like just moving any other
collection of files.

The main thing to consider is that working directories
point to the repository.  The simplest way to deal with
a moved repository is to just get a fresh working
directory after the move.  Of course, you'll want to
make sure that the old working directory had been
checked in before the move, or you figured out some
other way to make sure that you don't lose any
changes.  If you really do want to reuse the existing
working directory, it should be possible with manual
surgery on the @file{CVS/Repository} files.  You can
see @ref{Working directory storage}, for information on
the @file{CVS/Repository} and @file{CVS/Root} files, but
unless you are sure you want to bother, it probably
isn't worth it.
@c FIXME: Surgery on CVS/Repository should be avoided
@c by making RELATIVE_REPOS the default.
@c FIXME-maybe: might want some documented way to
@c change the CVS/Root files in some particular tree.
@c But then again, I don't know, maybe just having
@c people do this in perl/shell/&c isn't so bad...

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Remote repositories
@section Remote repositories
@cindex Repositories, remote
@cindex Remote repositories
@cindex Client/Server Operation
@cindex Server, CVS
@cindex Remote repositories, port specification
@cindex Repositories, remote, port specification
@cindex Client/Server Operation, port specification
@cindex pserver (client/server connection method), port specification
@cindex kserver (client/server connection method), port specification
@cindex gserver (client/server connection method), port specification
@cindex port, specifying for remote repositories

        Your working copy of the sources can be on a
different machine than the repository.  Using @sc{cvs}
in this manner is known as @dfn{client/server}
operation.  You run @sc{cvs} on a machine which can
mount your working directory, known as the
@dfn{client}, and tell it to communicate to a machine
which can mount the repository, known as the
@dfn{server}.  Generally, using a remote
repository is just like using a local one, except that
the format of the repository name is:

@example
[:@var{method}:][[@var{user}][:@var{password}]@@]@var{hostname}[:[@var{port}]]/path/to/repository
@end example

Specifying a password in the repository name is not recommended during
checkout, since this will cause @sc{cvs} to store a cleartext copy of the
password in each created directory.  @code{cvs login} first instead
(@pxref{Password authentication client}).

The details of exactly what needs to be set up depend
on how you are connecting to the server.

If @var{method} is not specified, and the repository
name contains @samp{:}, then the default is @code{ext}
or @code{server}, depending on your platform; both are
described in @ref{Connecting via rsh}.
@c Should we try to explain which platforms are which?
@c Platforms like unix and VMS, which only allow
@c privileged programs to bind to sockets <1024 lose on
@c :server:
@c Platforms like Mac and VMS, whose rsh program is
@c unusable or nonexistent, lose on :ext:
@c Platforms like OS/2 and NT probably could plausibly
@c default either way (modulo -b troubles).

@c FIXME: We need to have a better way of explaining
@c what method to use.  This presentation totally
@c obscures the fact that :ext: and CVS_RSH is the way to
@c use SSH, for example.  Plus it incorrectly implies
@c that you need an @code{rsh} binary on the client to use
@c :server:.
@c Also note that rsh not pserver is the right choice if you want
@c users to be able to create their own repositories
@c (because of the --allow-root related issues).
@menu
* Server requirements::         Memory and other resources for servers
* Connecting via rsh::          Using the @code{rsh} program to connect
* Password authenticated::      Direct connections using passwords
* GSSAPI authenticated::        Direct connections using GSSAPI
* Kerberos authenticated::      Direct connections with Kerberos
* Connecting via fork::         Using a forked @code{cvs server} to connect
@end menu

@node Server requirements
@subsection Server requirements

The quick answer to what sort of machine is suitable as
a server is that requirements are modest---a server
with 32M of memory or even less can handle a fairly
large source tree with a fair amount of activity.
@c Say something about CPU speed too?  I'm even less sure
@c what to say on that subject...

The real answer, of course, is more complicated.
Estimating the known areas of large memory consumption
should be sufficient to estimate memory requirements.
There are two such areas documented here; other memory
consumption should be small by comparison (if you find
that is not the case, let us know, as described in
@ref{BUGS}, so we can update this documentation).

The first area of big memory consumption is large
checkouts, when using the @sc{cvs} server.  The server
consists of two processes for each client that it is
serving.  Memory consumption on the child process
should remain fairly small.  Memory consumption on the
parent process, particularly if the network connection
to the client is slow, can be expected to grow to
slightly more than the size of the sources in a single
directory, or two megabytes, whichever is larger.
@c "two megabytes" of course is SERVER_HI_WATER.  But
@c we don't mention that here because we are
@c documenting the default configuration of CVS.  If it
@c is a "standard" thing to change that value, it
@c should be some kind of run-time configuration.
@c
@c See cvsclient.texi for more on the design decision
@c to not have locks in place while waiting for the
@c client, which is what results in memory consumption
@c as high as this.

Multiplying the size of each @sc{cvs} server by the
number of servers which you expect to have active at
one time should give an idea of memory requirements for
the server.  For the most part, the memory consumed by
the parent process probably can be swap space rather
than physical memory.
@c Has anyone verified that notion about swap space?
@c I say it based pretty much on guessing that the
@c ->text of the struct buffer_data only gets accessed
@c in a first in, first out fashion, but I haven't
@c looked very closely.

@c What about disk usage in /tmp on the server?  I think that
@c it can be substantial, but I haven't looked at this
@c again and tried to figure it out ("cvs import" is
@c probably the worst case...).

The second area of large memory consumption is
@code{diff}, when checking in large files.  This is
required even for binary files.  The rule of thumb is
to allow about ten times the size of the largest file
you will want to check in, although five times may be
adequate.  For example, if you want to check in a file
which is 10 megabytes, you should have 100 megabytes of
memory on the machine doing the checkin (the server
machine for client/server, or the machine running
@sc{cvs} for non-client/server).  This can be swap
space rather than physical memory.  Because the memory
is only required briefly, there is no particular need
to allow memory for more than one such checkin at a
time.
@c The 5-10 times rule of thumb is from Paul Eggert for
@c GNU diff.  I don't think it is in the GNU diff
@c manual or anyplace like that.
@c
@c Probably we could be saying more about
@c non-client/server CVS.
@c I would guess for non-client/server CVS in an NFS
@c environment the biggest issues are the network and
@c the NFS server.

Resource consumption for the client is even more
modest---any machine with enough capacity to run the
operating system in question should have little
trouble.
@c Is that true?  I think the client still wants to
@c (bogusly) store entire files in memory at times.

For information on disk space requirements, see
@ref{Creating a repository}.

@node Connecting via rsh
@subsection Connecting with rsh or ssh

@cindex ssh
@sc{cvs} may use the @samp{ssh} protocol to perform
these operations, so the remote user host needs to have
a either an agent like @code{ssh-agent} to hold
credentials or a @file{.shosts} file which grants
access to the local user. Note that the program that
@sc{cvs} uses for this purpose may be specified using
the @file{--with-ssh} flag to configure.

@cindex rsh
@sc{cvs} uses the @samp{rsh} protocol to perform these
operations, so the remote user host needs to have a
@file{.rhosts} file which grants access to the local
user. Note that the program that @sc{cvs} uses for this
purpose may be specified using the @file{--with-rsh}
flag to configure.

For example, suppose you are the user @samp{mozart} on
the local machine @samp{toe.example.com}, and the
server machine is @samp{faun.example.org}.  On
faun, put the following line into the file
@file{.rhosts} in @samp{bach}'s home directory:

@example
toe.example.com  mozart
@end example

@noindent
Then test that @samp{rsh} is working with

@example
rsh -l bach faun.example.org 'echo $PATH'
@end example

@noindent
To test that @samp{ssh} is working use

@example
ssh -l bach faun.example.org 'echo $PATH'
@end example

@cindex CVS_SERVER, environment variable
Next you have to make sure that @code{rsh} will be able
to find the server.  Make sure that the path which
@code{rsh} printed in the above example includes the
directory containing a program named @code{cvs} which
is the server.  You need to set the path in
@file{.bashrc}, @file{.cshrc}, etc., not @file{.login}
or @file{.profile}.  Alternately, you can set the
environment variable @code{CVS_SERVER} on the client
machine to the filename of the server you want to use,
for example @file{/usr/local/bin/cvs-1.6}.
@c FIXME: there should be a way to specify the
@c program in CVSROOT, not CVS_SERVER, so that one can use
@c different ones for different roots.  e.g. ":server;cvs=cvs-1.6:"
@c instead of ":server:".

There is no need to edit @file{inetd.conf} or start a
@sc{cvs} server daemon.

@cindex :server:, setting up
@cindex :ext:, setting up
@cindex :extssh:, setting up
@cindex Kerberos, using kerberized rsh
@cindex SSH (rsh replacement)
@cindex rsh replacements (Kerberized, SSH, &c)
There are three access methods that you use in @code{CVSROOT}
for rsh or ssh.  @code{:server:} specifies an internal rsh
client, which is supported only by some @sc{cvs} ports.
@code{:extssh:} specifies an external ssh program. By
default this is @code{ssh} (unless otherwise specified
by the @file{--with-ssh} flag to configure) but you may set the
@code{CVS_SSH} environment variable to invoke another
program or wrapper script.
@code{:ext:} specifies an external rsh program.  By
default this is @code{rsh} (unless otherwise specified
by the @file{--with-rsh} flag to configure) but you may set the
@code{CVS_RSH} environment variable to invoke another
program which can access the remote server (for
example, @code{remsh} on HP-UX 9 because @code{rsh} is
something different).  It must be a program which can
transmit data to and from the server without modifying
it; for example the Windows NT @code{rsh} is not
suitable since it by default translates between CRLF
and LF.  The OS/2 @sc{cvs} port has a hack to pass @samp{-b}
to @code{rsh} to get around this, but since this could
potentially cause problems for programs other than the
standard @code{rsh}, it may change in the future.  If
you set @code{CVS_RSH} to @code{SSH} or some other rsh
replacement, the instructions in the rest of this
section concerning @file{.rhosts} and so on are likely
to be inapplicable; consult the documentation for your rsh
replacement.
@c FIXME: there should be a way to specify the
@c program in CVSROOT, not CVS_RSH, so that one can use
@c different ones for different roots.  e.g.
@c ":ext;CVS_RSH=remsh:" instead of ":ext:".
@c See also the comment in src/client.c for rationale
@c concerning "rsh" being the default and never
@c "remsh".

Continuing our example, supposing you want to access
the module @file{foo} in the repository
@file{/usr/local/cvsroot/}, on machine
@file{faun.example.org}, you are ready to go:

@example
cvs -d :ext:bach@@faun.example.org:/usr/local/cvsroot checkout foo
@end example

@noindent
(The @file{bach@@} can be omitted if the username is
the same on both the local and remote hosts.)

@c Should we mention "rsh host echo hi" and "rsh host
@c cat" (the latter followed by typing text and ^D)
@c as troubleshooting techniques?  Probably yes
@c (people tend to have trouble setting this up),
@c but this kind of thing can be hard to spell out.

@node Password authenticated
@subsection Direct connection with password authentication

The @sc{cvs} client can also connect to the server
using a password protocol.  This is particularly useful
if using @code{rsh} is not feasible (for example,
the server is behind a firewall), and Kerberos also is
not available.

        To use this method, it is necessary to make
some adjustments on both the server and client sides.

@menu
* Password authentication server::     Setting up the server
* Password authentication client::     Using the client
* Password authentication security::   What this method does and does not do
@end menu

@node Password authentication server
@subsubsection Setting up the server for password authentication

First of all, you probably want to tighten the
permissions on the @file{$CVSROOT} and
@file{$CVSROOT/CVSROOT} directories.  See @ref{Password
authentication security}, for more details.

@cindex pserver (subcommand)
@cindex Remote repositories, port specification
@cindex Repositories, remote, port specification
@cindex Client/Server Operation, port specification
@cindex pserver (client/server connection method), port specification
@cindex kserver (client/server connection method), port specification
@cindex gserver (client/server connection method), port specification
@cindex port, specifying for remote repositories
@cindex Password server, setting up
@cindex Authenticating server, setting up
@cindex inetd, configuring for pserver
@cindex xinetd, configuring for pserver
@c FIXME: this isn't quite right regarding port
@c numbers; CVS looks up "cvspserver" in
@c /etc/services (on unix, but what about non-unix?).
On the server side, the file @file{/etc/inetd.conf}
needs to be edited so @code{inetd} knows to run the
command @code{cvs pserver} when it receives a
connection on the right port.  By default, the port
number is 2401; it would be different if your client
were compiled with @code{CVS_AUTH_PORT} defined to
something else, though.  This can also be specified in the CVSROOT variable
(@pxref{Remote repositories}) or overridden with the CVS_CLIENT_PORT
environment variable (@pxref{Environment variables}).

        If your @code{inetd} allows raw port numbers in
@file{/etc/inetd.conf}, then the following (all on a
single line in @file{inetd.conf}) should be sufficient:

@example
2401  stream  tcp  nowait  root  /usr/local/bin/cvs
cvs -f --allow-root=/usr/cvsroot pserver
@end example

@noindent
(You could also use the
@samp{-T} option to specify a temporary directory.)

The @samp{--allow-root} option specifies the allowable
@sc{cvsroot} directory.  Clients which attempt to use a
different @sc{cvsroot} directory will not be allowed to
connect.  If there is more than one @sc{cvsroot}
directory which you want to allow, repeat the option.
(Unfortunately, many versions of @code{inetd} have very small
limits on the number of arguments and/or the total length
of the command.  The usual solution to this problem is
to have @code{inetd} run a shell script which then invokes
@sc{cvs} with the necessary arguments.)

        If your @code{inetd} wants a symbolic service
name instead of a raw port number, then put this in
@file{/etc/services}:

@example
cvspserver      2401/tcp
@end example

@noindent
and put @code{cvspserver} instead of @code{2401} in @file{inetd.conf}.

If your system uses @code{xinetd} instead of @code{inetd},
the procedure is slightly different.
Create a file called @file{/etc/xinetd.d/cvspserver} containing the following:

@example
service cvspserver
@{
   port        = 2401
   socket_type = stream
   protocol    = tcp
   wait        = no
   user        = root
   passenv     = PATH
   server      = /usr/local/bin/cvs
   server_args = -f --allow-root=/usr/cvsroot pserver
@}
@end example

@noindent
(If @code{cvspserver} is defined in @file{/etc/services}, you can omit
the @code{port} line.)

        Once the above is taken care of, restart your
@code{inetd}, or do whatever is necessary to force it
to reread its initialization files.

If you are having trouble setting this up, see
@ref{Connection}.

@cindex CVS passwd file
@cindex passwd (admin file)
Because the client stores and transmits passwords in
cleartext (almost---see @ref{Password authentication
security}, for details), a separate @sc{cvs} password
file is generally used, so people don't compromise
their regular passwords when they access the
repository.  This file is
@file{$CVSROOT/CVSROOT/passwd} (@pxref{Intro
administrative files}).  It uses a colon-separated
format, similar to @file{/etc/passwd} on Unix systems,
except that it has fewer fields: @sc{cvs} username,
optional password, and an optional system username for
@sc{cvs} to run as if authentication succeeds.  Here is
an example @file{passwd} file with five entries:

@example
anonymous:
bach:ULtgRLXo7NRxs
spwang:1sOp854gDF3DY
melissa:tGX1fS8sun6rY:pubcvs
qproj:XR4EZcEs0szik:pubcvs
@end example

@noindent
(The passwords are encrypted according to the standard
Unix @code{crypt()} function, so it is possible to
paste in passwords directly from regular Unix
@file{/etc/passwd} files.)

The first line in the example will grant access to any
@sc{cvs} client attempting to authenticate as user
@code{anonymous}, no matter what password they use,
including an empty password.  (This is typical for
sites granting anonymous read-only access; for
information on how to do the "read-only" part, see
@ref{Read-only access}.)

The second and third lines will grant access to
@code{bach} and @code{spwang} if they supply their
respective plaintext passwords.

@cindex User aliases
The fourth line will grant access to @code{melissa}, if
she supplies the correct password, but her @sc{cvs}
operations will actually run on the server side under
the system user @code{pubcvs}.  Thus, there need not be
any system user named @code{melissa}, but there
@emph{must} be one named @code{pubcvs}.

The fifth line shows that system user identities can be
shared: any client who successfully authenticates as
@code{qproj} will actually run as @code{pubcvs}, just
as @code{melissa} does.  That way you could create a
single, shared system user for each project in your
repository, and give each developer their own line in
the @file{$CVSROOT/CVSROOT/passwd} file.  The @sc{cvs}
username on each line would be different, but the
system username would be the same.  The reason to have
different @sc{cvs} usernames is that @sc{cvs} will log their
actions under those names: when @code{melissa} commits
a change to a project, the checkin is recorded in the
project's history under the name @code{melissa}, not
@code{pubcvs}.  And the reason to have them share a
system username is so that you can arrange permissions
in the relevant area of the repository such that only
that account has write-permission there.

If the system-user field is present, all
password-authenticated @sc{cvs} commands run as that
user; if no system user is specified, @sc{cvs} simply
takes the @sc{cvs} username as the system username and
runs commands as that user.  In either case, if there
is no such user on the system, then the @sc{cvs}
operation will fail (regardless of whether the client
supplied a valid password).

The password and system-user fields can both be omitted
(and if the system-user field is omitted, then also
omit the colon that would have separated it from the
encrypted password).  For example, this would be a
valid @file{$CVSROOT/CVSROOT/passwd} file:

@example
anonymous::pubcvs
fish:rKa5jzULzmhOo:kfogel
sussman:1sOp854gDF3DY
@end example

@noindent
When the password field is omitted or empty, then the
client's authentication attempt will succeed with any
password, including the empty string.  However, the
colon after the @sc{cvs} username is always necessary,
even if the password is empty.

@sc{cvs} can also fall back to use system authentication.
When authenticating a password, the server first checks
for the user in the @file{$CVSROOT/CVSROOT/passwd}
file.  If it finds the user, it will use that entry for
authentication as described above.  But if it does not
find the user, or if the @sc{cvs} @file{passwd} file
does not exist, then the server can try to authenticate
the username and password using the operating system's
user-lookup routines (this "fallback" behavior can be
disabled by setting @code{SystemAuth=no} in the
@sc{cvs} @file{config} file, @pxref{config}).  Be
aware, however, that falling back to system
authentication might be a security risk: @sc{cvs}
operations would then be authenticated with that user's
regular login password, and the password flies across
the network in plaintext.  See @ref{Password
authentication security} for more on this.

Right now, the only way to put a password in the
@sc{cvs} @file{passwd} file is to paste it there from
somewhere else.  Someday, there may be a @code{cvs
passwd} command.

Unlike many of the files in @file{$CVSROOT/CVSROOT}, it
is normal to edit the @file{passwd} file in-place,
rather than via @sc{cvs}.  This is because of the
possible security risks of having the @file{passwd}
file checked out to people's working copies.  If you do
want to include the @file{passwd} file in checkouts of
@file{$CVSROOT/CVSROOT}, see @ref{checkoutlist}.

@c We might also suggest using the @code{htpasswd} command
@c from freely available web servers as well, but that
@c would open up a can of worms in that the users next
@c questions are likely to be "where do I get it?" and
@c "how do I use it?"
@c Also note that htpasswd, at least the version I had,
@c likes to clobber the third field.

@node Password authentication client
@subsubsection Using the client with password authentication
@cindex Login (subcommand)
@cindex Password client, using
@cindex Authenticated client, using
@cindex :pserver:, setting up
To run a @sc{cvs} command on a remote repository via
the password-authenticating server, one specifies the
@code{pserver} protocol, optional username, repository host, an
optional port number, and path to the repository.  For example:

@example
cvs -d :pserver:faun.example.org:/usr/local/cvsroot checkout someproj
@end example

@noindent
or

@example
CVSROOT=:pserver:bach@@faun.example.org:2401/usr/local/cvsroot
cvs checkout someproj
@end example

However, unless you're connecting to a public-access
repository (i.e., one where that username doesn't
require a password), you'll need to supply a password or @dfn{log in} first.
Logging in verifies your password with the repository and stores it in a file.
It's done with the @code{login} command, which will
prompt you interactively for the password if you didn't supply one as part of
@var{$CVSROOT}:

@example
cvs -d :pserver:bach@@faun.example.org:/usr/local/cvsroot login
CVS password:
@end example

@noindent
or

@example
cvs -d :pserver:bach:p4ss30rd@@faun.example.org:/usr/local/cvsroot login
@end example

After you enter the password, @sc{cvs} verifies it with
the server.  If the verification succeeds, then that
combination of username, host, repository, and password
is permanently recorded, so future transactions with
that repository won't require you to run @code{cvs
login}.  (If verification fails, @sc{cvs} will exit
complaining that the password was incorrect, and
nothing will be recorded.)

The records are stored, by default, in the file
@file{$HOME/.cvspass}.  That file's format is
human-readable, and to a degree human-editable, but
note that the passwords are not stored in
cleartext---they are trivially encoded to protect them
from "innocent" compromise (i.e., inadvertent viewing
by a system administrator or other non-malicious
person).

@cindex CVS_PASSFILE, environment variable
You can change the default location of this file by
setting the @code{CVS_PASSFILE} environment variable.
If you use this variable, make sure you set it
@emph{before} @code{cvs login} is run.  If you were to
set it after running @code{cvs login}, then later
@sc{cvs} commands would be unable to look up the
password for transmission to the server.
  
Once you have logged in, all @sc{cvs} commands using
that remote repository and username will authenticate
with the stored password.  So, for example
  
@example
cvs -d :pserver:bach@@faun.example.org:/usr/local/cvsroot checkout foo
@end example

@noindent
should just work (unless the password changes on the
server side, in which case you'll have to re-run
@code{cvs login}).

Note that if the @samp{:pserver:} were not present in
the repository specification, @sc{cvs} would assume it
should use @code{rsh} to connect with the server
instead (@pxref{Connecting via rsh}).

Of course, once you have a working copy checked out and
are running @sc{cvs} commands from within it, there is
no longer any need to specify the repository
explicitly, because @sc{cvs} can deduce the repository
from the working copy's @file{CVS} subdirectory.

@c FIXME: seems to me this needs somewhat more
@c explanation.
@cindex Logout (subcommand)
The password for a given remote repository can be
removed from the @code{CVS_PASSFILE} by using the
@code{cvs logout} command.

@node Password authentication security
@subsubsection Security considerations with password authentication

@cindex Security, of pserver
The passwords are stored on the client side in a
trivial encoding of the cleartext, and transmitted in
the same encoding.  The encoding is done only to
prevent inadvertent password compromises (i.e., a
system administrator accidentally looking at the file),
and will not prevent even a naive attacker from gaining
the password.

@c FIXME: The bit about "access to the repository
@c implies general access to the system is *not* specific
@c to pserver; it applies to kerberos and SSH and
@c everything else too.  Should reorganize the
@c documentation to make this clear.
The separate @sc{cvs} password file (@pxref{Password
authentication server}) allows people
to use a different password for repository access than
for login access.  On the other hand, once a user has
non-read-only
access to the repository, she can execute programs on
the server system through a variety of means.  Thus, repository
access implies fairly broad system access as well.  It
might be possible to modify @sc{cvs} to prevent that,
but no one has done so as of this writing.
@c OpenBSD uses chroot() and copies the repository to
@c provide anonymous read-only access (for details see
@c http://www.openbsd.org/anoncvs.shar).  While this
@c closes the most obvious holes, I'm not sure it
@c closes enough holes to recommend it (plus it is
@c *very* easy to accidentally screw up a setup of this
@c type).

Note that because the @file{$CVSROOT/CVSROOT} directory
contains @file{passwd} and other files which are used
to check security, you must control the permissions on
this directory as tightly as the permissions on
@file{/etc}.  The same applies to the @file{$CVSROOT}
directory itself and any directory
above it in the tree.  Anyone who has write access to
such a directory will have the ability to become any
user on the system.  Note that these permissions are
typically tighter than you would use if you are not
using pserver.
@c TODO: Would be really nice to document/implement a
@c scheme where the CVS server can run as some non-root
@c user, e.g. "cvs".  CVSROOT/passwd would contain a
@c bunch of entries of the form foo:xxx:cvs (or the "cvs"
@c would be implicit).  This would greatly reduce
@c security risks such as those hinted at in the
@c previous paragraph.  I think minor changes to CVS
@c might be required but mostly this would just need
@c someone who wants to play with it, document it, &c.

In summary, anyone who gets the password gets
repository access (which may imply some measure of general system
access as well).  The password is available to anyone
who can sniff network packets or read a protected
(i.e., user read-only) file.  If you want real
security, get Kerberos.

@node GSSAPI authenticated
@subsection Direct connection with GSSAPI

@cindex GSSAPI
@cindex Security, GSSAPI
@cindex :gserver:, setting up
@cindex Kerberos, using :gserver:
GSSAPI is a generic interface to network security
systems such as Kerberos 5.
If you have a working GSSAPI library, you can have
@sc{cvs} connect via a direct @sc{tcp} connection,
authenticating with GSSAPI.

To do this, @sc{cvs} needs to be compiled with GSSAPI
support; when configuring @sc{cvs} it tries to detect
whether GSSAPI libraries using Kerberos version 5 are
present.  You can also use the @file{--with-gssapi}
flag to configure.

The connection is authenticated using GSSAPI, but the
message stream is @emph{not} authenticated by default.
You must use the @code{-a} global option to request
stream authentication.

The data transmitted is @emph{not} encrypted by
default.  Encryption support must be compiled into both
the client and the server; use the
@file{--enable-encrypt} configure option to turn it on.
You must then use the @code{-x} global option to
request encryption.

GSSAPI connections are handled on the server side by
the same server which handles the password
authentication server; see @ref{Password authentication
server}.  If you are using a GSSAPI mechanism such as
Kerberos which provides for strong authentication, you
will probably want to disable the ability to
authenticate via cleartext passwords.  To do so, create
an empty @file{CVSROOT/passwd} password file, and set
@code{SystemAuth=no} in the config file
(@pxref{config}).

The GSSAPI server uses a principal name of
cvs/@var{hostname}, where @var{hostname} is the
canonical name of the server host.  You will have to
set this up as required by your GSSAPI mechanism.

To connect using GSSAPI, use the @samp{:gserver:} method.  For
example,

@example
cvs -d :gserver:faun.example.org:/usr/local/cvsroot checkout foo
@end example

@node Kerberos authenticated
@subsection Direct connection with Kerberos

@cindex Kerberos, using :kserver:
@cindex Security, Kerberos
@cindex :kserver:, setting up
The easiest way to use Kerberos is to use the Kerberos
@code{rsh}, as described in @ref{Connecting via rsh}.
The main disadvantage of using rsh is that all the data
needs to pass through additional programs, so it may be
slower.  So if you have Kerberos installed you can
connect via a direct @sc{tcp} connection,
authenticating with Kerberos.

This section concerns the Kerberos network security
system, version 4.  Kerberos version 5 is supported via
the GSSAPI generic network security interface, as
described in the previous section.

To do this, @sc{cvs} needs to be compiled with Kerberos
support; when configuring @sc{cvs} it tries to detect
whether Kerberos is present or you can use the
@file{--with-krb4} flag to configure.

The data transmitted is @emph{not} encrypted by
default.  Encryption support must be compiled into both
the client and server; use the
@file{--enable-encryption} configure option to turn it
on.  You must then use the @code{-x} global option to
request encryption.

@cindex CVS_CLIENT_PORT
You need to edit @file{inetd.conf} on the server
machine to run @code{cvs kserver}.  The client uses
port 1999 by default; if you want to use another port
specify it in the @code{CVSROOT} (@pxref{Remote repositories})
or the @code{CVS_CLIENT_PORT} environment variable
(@pxref{Environment variables}) on the client.

@cindex kinit
When you want to use @sc{cvs}, get a ticket in the
usual way (generally @code{kinit}); it must be a ticket
which allows you to log into the server machine.  Then
you are ready to go:

@example
cvs -d :kserver:faun.example.org:/usr/local/cvsroot checkout foo
@end example

Previous versions of @sc{cvs} would fall back to a
connection via rsh; this version will not do so.

@node Connecting via fork
@subsection Connecting with fork

@cindex fork, access method
@cindex :fork:, setting up
This access method allows you to connect to a
repository on your local disk via the remote protocol.
In other words it does pretty much the same thing as
@code{:local:}, but various quirks, bugs and the like are
those of the remote @sc{cvs} rather than the local
@sc{cvs}.

For day-to-day operations you might prefer either
@code{:local:} or @code{:fork:}, depending on your
preferences.  Of course @code{:fork:} comes in
particularly handy in testing or
debugging @code{cvs} and the remote protocol.
Specifically, we avoid all of the network-related
setup/configuration, timeouts, and authentication
inherent in the other remote access methods but still
create a connection which uses the remote protocol.

To connect using the @code{fork} method, use
@samp{:fork:} and the pathname to your local
repository.  For example:

@example
cvs -d :fork:/usr/local/cvsroot checkout foo
@end example

@cindex CVS_SERVER, and :fork:
As with @code{:ext:}, the server is called @samp{cvs}
by default, or the value of the @code{CVS_SERVER}
environment variable.

@c ---------------------------------------------------------------------
@node Read-only access
@section Read-only repository access
@cindex Read-only repository access
@cindex readers (admin file)
@cindex writers (admin file)

        It is possible to grant read-only repository
access to people using the password-authenticated
server (@pxref{Password authenticated}).  (The
other access methods do not have explicit support for
read-only users because those methods all assume login
access to the repository machine anyway, and therefore
the user can do whatever local file permissions allow
her to do.)

        A user who has read-only access can do only
those @sc{cvs} operations which do not modify the
repository, except for certain ``administrative'' files
(such as lock files and the history file).  It may be
desirable to use this feature in conjunction with
user-aliasing (@pxref{Password authentication server}).

Unlike with previous versions of @sc{cvs}, read-only
users should be able merely to read the repository, and
not to execute programs on the server or otherwise gain
unexpected levels of access.  Or to be more accurate,
the @emph{known} holes have been plugged.  Because this
feature is new and has not received a comprehensive
security audit, you should use whatever level of
caution seems warranted given your attitude concerning
security.

        There are two ways to specify read-only access
for a user: by inclusion, and by exclusion.

        "Inclusion" means listing that user
specifically in the @file{$CVSROOT/CVSROOT/readers}
file, which is simply a newline-separated list of
users.  Here is a sample @file{readers} file:

@example
melissa
splotnik
jrandom
@end example

@noindent
        (Don't forget the newline after the last user.)

        "Exclusion" means explicitly listing everyone
who has @emph{write} access---if the file

@example
$CVSROOT/CVSROOT/writers
@end example

@noindent
exists, then only
those users listed in it have write access, and
everyone else has read-only access (of course, even the
read-only users still need to be listed in the
@sc{cvs} @file{passwd} file).  The
@file{writers} file has the same format as the
@file{readers} file.

        Note: if your @sc{cvs} @file{passwd}
file maps cvs users onto system users (@pxref{Password
authentication server}), make sure you deny or grant
read-only access using the @emph{cvs} usernames, not
the system usernames.  That is, the @file{readers} and
@file{writers} files contain cvs usernames, which may
or may not be the same as system usernames.

        Here is a complete description of the server's
behavior in deciding whether to grant read-only or
read-write access:

        If @file{readers} exists, and this user is
listed in it, then she gets read-only access.  Or if
@file{writers} exists, and this user is NOT listed in
it, then she also gets read-only access (this is true
even if @file{readers} exists but she is not listed
there).  Otherwise, she gets full read-write access.

        Of course there is a conflict if the user is
listed in both files.  This is resolved in the more
conservative way, it being better to protect the
repository too much than too little: such a user gets
read-only access.

@node Server temporary directory
@section Temporary directories for the server
@cindex Temporary directories, and server
@cindex Server, temporary directories

While running, the @sc{cvs} server creates temporary
directories.  They are named

@example
cvs-serv@var{pid}
@end example

@noindent
where @var{pid} is the process identification number of
the server.
They are located in the directory specified by 
the @samp{-T} global option (@pxref{Global options}), 
the @code{TMPDIR} environment variable (@pxref{Environment variables}), 
or, failing that, @file{/tmp}.

In most cases the server will remove the temporary
directory when it is done, whether it finishes normally
or abnormally.  However, there are a few cases in which
the server does not or cannot remove the temporary
directory, for example:

@itemize @bullet
@item
If the server aborts due to an internal server error,
it may preserve the directory to aid in debugging

@item
If the server is killed in a way that it has no way of
cleaning up (most notably, @samp{kill -KILL} on unix).

@item
If the system shuts down without an orderly shutdown,
which tells the server to clean up.
@end itemize

In cases such as this, you will need to manually remove
the @file{cvs-serv@var{pid}} directories.  As long as
there is no server running with process identification
number @var{pid}, it is safe to do so.

@c ---------------------------------------------------------------------
@node Starting a new project
@chapter Starting a project with CVS
@cindex Starting a project with CVS
@cindex Creating a project

@comment --moduledb--
Because renaming files and moving them between
directories is somewhat inconvenient, the first thing
you do when you start a new project should be to think
through your file organization.  It is not impossible
to rename or move files, but it does increase the
potential for confusion and @sc{cvs} does have some
quirks particularly in the area of renaming
directories.  @xref{Moving files}.

What to do next depends on the situation at hand.

@menu
* Setting up the files::        Getting the files into the repository
* Defining the module::         How to make a module of the files
@end menu
@c -- File permissions!

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Setting up the files
@section Setting up the files

The first step is to create the files inside the repository.  This can
be done in a couple of different ways.

@c -- The contributed scripts
@menu
* From files::                  This method is useful with old projects
                                where files already exists.
* From other version control systems::  Old projects where you want to
                                        preserve history from another system.
* From scratch::                Creating a directory tree from scratch.
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node From files
@subsection Creating a directory tree from a number of files
@cindex Importing files

When you begin using @sc{cvs}, you will probably already have several
projects that can be
put under @sc{cvs} control.  In these cases the easiest way is to use the
@code{import} command.  An example is probably the easiest way to
explain how to use it.  If the files you want to install in
@sc{cvs} reside in @file{@var{wdir}}, and you want them to appear in the
repository as @file{$CVSROOT/yoyodyne/@var{rdir}}, you can do this:

@example
$ cd @var{wdir}
$ cvs import -m "Imported sources" yoyodyne/@var{rdir} yoyo start
@end example

Unless you supply a log message with the @samp{-m}
flag, @sc{cvs} starts an editor and prompts for a
message.  The string @samp{yoyo} is a @dfn{vendor tag},
and @samp{start} is a @dfn{release tag}.  They may fill
no purpose in this context, but since @sc{cvs} requires
them they must be present.  @xref{Tracking sources}, for
more information about them.

You can now verify that it worked, and remove your
original source directory.
@c FIXME: Need to say more about "verify that it
@c worked".  What should the user look for in the output
@c from "diff -r"?

@example
$ cd ..
$ cvs checkout yoyodyne/@var{rdir}       # @r{Explanation below}
$ diff -r @var{wdir} yoyodyne/@var{rdir}
$ rm -r @var{wdir}
@end example

@noindent
Erasing the original sources is a good idea, to make sure that you do
not accidentally edit them in @var{wdir}, bypassing @sc{cvs}.
Of course, it would be wise to make sure that you have
a backup of the sources before you remove them.

The @code{checkout} command can either take a module
name as argument (as it has done in all previous
examples) or a path name relative to @code{$CVSROOT},
as it did in the example above.

It is a good idea to check that the permissions
@sc{cvs} sets on the directories inside @code{$CVSROOT}
are reasonable, and that they belong to the proper
groups.  @xref{File permissions}.

If some of the files you want to import are binary, you
may want to use the wrappers features to specify which
files are binary and which are not.  @xref{Wrappers}.

@c The node name is too long, but I am having trouble
@c thinking of something more concise.
@node From other version control systems
@subsection Creating Files From Other Version Control Systems
@cindex Importing files, from other version control systems

If you have a project which you are maintaining with
another version control system, such as @sc{rcs}, you
may wish to put the files from that project into
@sc{cvs}, and preserve the revision history of the
files.

@table @asis
@cindex RCS, importing files from
@item From RCS
If you have been using @sc{rcs}, find the @sc{rcs}
files---usually a file named @file{foo.c} will have its
@sc{rcs} file in @file{RCS/foo.c,v} (but it could be
other places; consult the @sc{rcs} documentation for
details).  Then create the appropriate directories in
@sc{cvs} if they do not already exist.  Then copy the
files into the appropriate directories in the @sc{cvs}
repository (the name in the repository must be the name
of the source file with @samp{,v} added; the files go
directly in the appropriate directory of the repository,
not in an @file{RCS} subdirectory).  This is one of the
few times when it is a good idea to access the @sc{cvs}
repository directly, rather than using @sc{cvs}
commands.  Then you are ready to check out a new
working directory.
@c Someday there probably should be a "cvs import -t
@c rcs" or some such.  It could even create magic
@c branches.  It could also do something about the case
@c where the RCS file had a (non-magic) "0" branch.

The @sc{rcs} file should not be locked when you move it
into @sc{cvs}; if it is, @sc{cvs} will have trouble
letting you operate on it.
@c What is the easiest way to unlock your files if you
@c have them locked?  Especially if you have a lot of them?
@c This is a CVS bug/misfeature; importing RCS files
@c should ignore whether they are locked and leave them in
@c an unlocked state.  Yet another reason for a separate
@c "import RCS file" command.

@c How many is "many"? Or do they just import RCS files?
@item From another version control system
Many version control systems have the ability to export
@sc{rcs} files in the standard format.  If yours does,
export the @sc{rcs} files and then follow the above
instructions.

Failing that, probably your best bet is to write a
script that will check out the files one revision at a
time using the command line interface to the other
system, and then check the revisions into @sc{cvs}.
The @file{sccs2rcs} script mentioned below may be a
useful example to follow.

@cindex SCCS, importing files from
@item From SCCS
There is a script in the @file{contrib} directory of
the @sc{cvs} source distribution called @file{sccs2rcs}
which converts @sc{sccs} files to @sc{rcs} files.
Note: you must run it on a machine which has both
@sc{sccs} and @sc{rcs} installed, and like everything
else in contrib it is unsupported (your mileage may
vary).

@cindex PVCS, importing files from
@item From PVCS
There is a script in the @file{contrib} directory of
the @sc{cvs} source distribution called @file{pvcs_to_rcs}
which converts @sc{pvcs} archives to @sc{rcs} files.
You must run it on a machine which has both
@sc{pvcs} and @sc{rcs} installed, and like everything
else in contrib it is unsupported (your mileage may
vary).  See the comments in the script for details.
@end table
@c CMZ and/or PATCHY were systems that were used in the
@c high energy physics community (especially for
@c CERNLIB).  CERN has replaced them with CVS, but the
@c CAR format seems to live on as a way to submit
@c changes.  There is a program car2cvs which converts
@c but I'm not sure where one gets a copy.
@c Not sure it is worth mentioning here, since it would
@c appear to affect only one particular community.
@c Best page for more information is:
@c http://wwwcn1.cern.ch/asd/cvs/index.html
@c See also:
@c http://ecponion.cern.ch/ecpsa/cernlib.html

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node From scratch
@subsection Creating a directory tree from scratch

@c Also/instead should be documenting
@c $ cvs co -l .
@c $ mkdir tc
@c $ cvs add tc
@c $ cd tc
@c $ mkdir man
@c $ cvs add man
@c etc.
@c Using import to create the directories only is
@c probably a somewhat confusing concept.
For a new project, the easiest thing to do is probably
to create an empty directory structure, like this:

@example
$ mkdir tc
$ mkdir tc/man
$ mkdir tc/testing
@end example

After that, you use the @code{import} command to create
the corresponding (empty) directory structure inside
the repository:

@example
$ cd tc
$ cvs import -m "Created directory structure" yoyodyne/@var{dir} yoyo start
@end example

This will add yoyodyne/@var{dir} as a directory under
@code{$CVSROOT}.

Use @code{checkout} to get the new project.  Then, use @code{add}
to add files (and new directories) as needed.

@example
$ cd ..
$ cvs co yoyodyne/@var{dir}
@end example

Check that the permissions @sc{cvs} sets on the
directories inside @code{$CVSROOT} are reasonable.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Defining the module
@section Defining the module
@cindex Defining a module
@cindex Editing the modules file
@cindex Module, defining
@cindex Modules file, changing

The next step is to define the module in the
@file{modules} file.  This is not strictly necessary,
but modules can be convenient in grouping together
related files and directories.

In simple cases these steps are sufficient to define a module.

@enumerate
@item
Get a working copy of the modules file.

@example
$ cvs checkout CVSROOT/modules
$ cd CVSROOT
@end example

@item
Edit the file and insert a line that defines the module.  @xref{Intro
administrative files}, for an introduction.  @xref{modules}, for a full
description of the modules file.  You can use the
following line to define the module @samp{tc}:

@example
tc   yoyodyne/tc
@end example

@item
Commit your changes to the modules file.

@example
$ cvs commit -m "Added the tc module." modules
@end example

@item
Release the modules module.

@example
$ cd ..
$ cvs release -d CVSROOT
@end example
@end enumerate

@c ---------------------------------------------------------------------
@node Revisions
@chapter Revisions

For many uses of @sc{cvs}, one doesn't need to worry
too much about revision numbers; @sc{cvs} assigns
numbers such as @code{1.1}, @code{1.2}, and so on, and
that is all one needs to know.  However, some people
prefer to have more knowledge and control concerning
how @sc{cvs} assigns revision numbers.

If one wants to keep track of a set of revisions
involving more than one file, such as which revisions
went into a particular release, one uses a @dfn{tag},
which is a symbolic revision which can be assigned to a
numeric revision in each file.

@menu
* Revision numbers::            The meaning of a revision number
* Versions revisions releases::  Terminology used in this manual
* Assigning revisions::         Assigning revisions
* Tags::                        Tags--Symbolic revisions
* Tagging the working directory::  The cvs tag command
* Tagging by date/tag::         The cvs rtag command
* Modifying tags::              Adding, renaming, and deleting tags
* Tagging add/remove::          Tags with adding and removing files
* Sticky tags::                 Certain tags are persistent
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Revision numbers
@section Revision numbers
@cindex Revision numbers
@cindex Revision tree
@cindex Linear development
@cindex Number, revision-
@cindex Decimal revision number
@cindex Branch number
@cindex Number, branch

Each version of a file has a unique @dfn{revision
number}.  Revision numbers look like @samp{1.1},
@samp{1.2}, @samp{1.3.2.2} or even @samp{1.3.2.2.4.5}.
A revision number always has an even number of
period-separated decimal integers.  By default revision
1.1 is the first revision of a file.  Each successive
revision is given a new number by increasing the
rightmost number by one.  The following figure displays
a few revisions, with newer revisions to the right.

@example
       +-----+    +-----+    +-----+    +-----+    +-----+
       ! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !
       +-----+    +-----+    +-----+    +-----+    +-----+
@end example

It is also possible to end up with numbers containing
more than one period, for example @samp{1.3.2.2}.  Such
revisions represent revisions on branches
(@pxref{Branching and merging}); such revision numbers
are explained in detail in @ref{Branches and
revisions}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Versions revisions releases
@section Versions, revisions and releases
@cindex Revisions, versions and releases
@cindex Versions, revisions and releases
@cindex Releases, revisions and versions

A file can have several versions, as described above.
Likewise, a software product can have several versions.
A software product is often given a version number such
as @samp{4.1.1}.

Versions in the first sense are called @dfn{revisions}
in this document, and versions in the second sense are
called @dfn{releases}.  To avoid confusion, the word
@dfn{version} is almost never used in this document.

@node Assigning revisions
@section Assigning revisions

@c We avoid the "major revision" terminology.  It seems
@c like jargon.  Hopefully "first number" is clear enough.
By default, @sc{cvs} will assign numeric revisions by
leaving the first number the same and incrementing the
second number.  For example, @code{1.1}, @code{1.2},
@code{1.3}, etc.

When adding a new file, the second number will always
be one and the first number will equal the highest
first number of any file in that directory.  For
example, the current directory contains files whose
highest numbered revisions are @code{1.7}, @code{3.1},
and @code{4.12}, then an added file will be given the
numeric revision @code{4.1}.
(When using client/server @sc{cvs},
only files that are actually sent to the server are considered.)

@c This is sort of redundant with something we said a
@c while ago.  Somewhere we need a better way of
@c introducing how the first number can be anything
@c except "1", perhaps.  Also I don't think this
@c presentation is clear on why we are discussing releases
@c and first numbers of numeric revisions in the same
@c breath.
Normally there is no reason to care
about the revision numbers---it is easier to treat them
as internal numbers that @sc{cvs} maintains, and tags
provide a better way to distinguish between things like
release 1 versus release 2 of your product
(@pxref{Tags}).  However, if you want to set the
numeric revisions, the @samp{-r} option to @code{cvs
commit} can do that.  The @samp{-r} option implies the
@samp{-f} option, in the sense that it causes the
files to be committed even if they are not modified.

For example, to bring all your files up to
revision 3.0 (including those that haven't changed),
you might invoke:

@example
$ cvs commit -r 3.0
@end example

Note that the number you specify with @samp{-r} must be
larger than any existing revision number.  That is, if
revision 3.0 exists, you cannot @samp{cvs commit
-r 1.3}.  If you want to maintain several releases in
parallel, you need to use a branch (@pxref{Branching and merging}).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Tags
@section Tags--Symbolic revisions
@cindex Tags

The revision numbers live a life of their own.  They
need not have anything at all to do with the release
numbers of your software product.  Depending
on how you use @sc{cvs} the revision numbers might change several times
between two releases.  As an example, some of the
source files that make up @sc{rcs} 5.6 have the following
revision numbers:
@cindex RCS revision numbers

@example
ci.c            5.21
co.c            5.9
ident.c         5.3
rcs.c           5.12
rcsbase.h       5.11
rcsdiff.c       5.10
rcsedit.c       5.11
rcsfcmp.c       5.9
rcsgen.c        5.10
rcslex.c        5.11
rcsmap.c        5.2
rcsutil.c       5.10
@end example

@cindex tag, command, introduction
@cindex Tag, symbolic name
@cindex Symbolic name (tag)
@cindex Name, symbolic (tag)
@cindex HEAD, as reserved tag name
@cindex BASE, as reserved tag name
You can use the @code{tag} command to give a symbolic name to a
certain revision of a file.  You can use the @samp{-v} flag to the
@code{status} command to see all tags that a file has, and
which revision numbers they represent.  Tag names must
start with an uppercase or lowercase letter and can
contain uppercase and lowercase letters, digits,
@samp{-}, and @samp{_}.  The two tag names @code{BASE}
and @code{HEAD} are reserved for use by @sc{cvs}.  It
is expected that future names which are special to
@sc{cvs} will be specially named, for example by
starting with @samp{.}, rather than being named analogously to
@code{BASE} and @code{HEAD}, to avoid conflicts with
actual tag names.
@c Including a character such as % or = has also been
@c suggested as the naming convention for future
@c special tag names.  Starting with . is nice because
@c that is not a legal tag name as far as RCS is concerned.
@c FIXME: CVS actually accepts quite a few characters
@c in tag names, not just the ones documented above
@c (see RCS_check_tag).  RCS
@c defines legitimate tag names by listing illegal
@c characters rather than legal ones.  CVS is said to lose its
@c mind if you try to use "/" (try making such a tag sticky
@c and using "cvs status" client/server--see remote
@c protocol format for entries line for probable cause).
@c TODO: The testsuite
@c should test for whatever are documented above as
@c officially-OK tag names, and CVS should at least reject
@c characters that won't work, like "/".

You'll want to choose some convention for naming tags,
based on information such as the name of the program
and the version number of the release.  For example,
one might take the name of the program, immediately
followed by the version number with @samp{.} changed to
@samp{-}, so that @sc{cvs} 1.9 would be tagged with the name
@code{cvs1-9}.  If you choose a consistent convention,
then you won't constantly be guessing whether a tag is
@code{cvs-1-9} or @code{cvs1_9} or what.  You might
even want to consider enforcing your convention in the
@file{taginfo} file (@pxref{taginfo}).
@c Might be nice to say more about using taginfo this
@c way, like giving an example, or pointing out any particular
@c issues which arise.

@cindex Adding a tag
@cindex Tag, example
The following example shows how you can add a tag to a
file.  The commands must be issued inside your working
directory.  That is, you should issue the
command in the directory where @file{backend.c}
resides.

@example
$ cvs tag rel-0-4 backend.c
T backend.c
$ cvs status -v backend.c
===================================================================
File: backend.c         Status: Up-to-date

    Version:            1.4     Tue Dec  1 14:39:01 1992
    RCS Version:        1.4     /u/cvsroot/yoyodyne/tc/backend.c,v
    Sticky Tag:         (none)
    Sticky Date:        (none)
    Sticky Options:     (none)

    Existing Tags:
        rel-0-4                     (revision: 1.4)

@end example

For a complete summary of the syntax of @code{cvs tag},
including the various options, see @ref{Invoking CVS}.

There is seldom reason to tag a file in isolation.  A more common use is
to tag all the files that constitute a module with the same tag at
strategic points in the development life-cycle, such as when a release
is made.

@example
$ cvs tag rel-1-0 .
cvs tag: Tagging .
T Makefile
T backend.c
T driver.c
T frontend.c
T parser.c
@end example

@noindent
(When you give @sc{cvs} a directory as argument, it generally applies the
operation to all the files in that directory, and (recursively), to any
subdirectories that it may contain.  @xref{Recursive behavior}.)

@cindex Retrieving an old revision using tags
@cindex Tag, retrieving old revisions
The @code{checkout} command has a flag, @samp{-r}, that lets you check out
a certain revision of a module.  This flag makes it easy to
retrieve the sources that make up release 1.0 of the module @samp{tc} at
any time in the future:

@example
$ cvs checkout -r rel-1-0 tc
@end example

@noindent
This is useful, for instance, if someone claims that there is a bug in
that release, but you cannot find the bug in the current working copy.

You can also check out a module as it was at any given date.
@xref{checkout options}.  When specifying @samp{-r} to
any of these commands, you will need beware of sticky
tags; see @ref{Sticky tags}.

When you tag more than one file with the same tag you
can think about the tag as "a curve drawn through a
matrix of filename vs.@: revision number."  Say we have 5
files with the following revisions:

@example
@group
        file1   file2   file3   file4   file5

        1.1     1.1     1.1     1.1  /--1.1*      <-*-  TAG
        1.2*-   1.2     1.2    -1.2*-
        1.3  \- 1.3*-   1.3   / 1.3
        1.4          \  1.4  /  1.4
                      \-1.5*-   1.5
                        1.6
@end group
@end example

At some time in the past, the @code{*} versions were tagged.
You can think of the tag as a handle attached to the curve
drawn through the tagged revisions.  When you pull on
the handle, you get all the tagged revisions.  Another
way to look at it is that you "sight" through a set of
revisions that is "flat" along the tagged revisions,
like this:

@example
@group
        file1   file2   file3   file4   file5

                        1.1
                        1.2
                1.1     1.3                       _
        1.1     1.2     1.4     1.1              /
        1.2*----1.3*----1.5*----1.2*----1.1     (--- <--- Look here
        1.3             1.6     1.3              \_
        1.4                     1.4
                                1.5
@end group
@end example

@node Tagging the working directory
@section Specifying what to tag from the working directory

@cindex tag (subcommand)
The example in the previous section demonstrates one of
the most common ways to choose which revisions to tag.
Namely, running the @code{cvs tag} command without
arguments causes @sc{cvs} to select the revisions which
are checked out in the current working directory.  For
example, if the copy of @file{backend.c} in working
directory was checked out from revision 1.4, then
@sc{cvs} will tag revision 1.4.  Note that the tag is
applied immediately to revision 1.4 in the repository;
tagging is not like modifying a file, or other
operations in which one first modifies the working
directory and then runs @code{cvs commit} to transfer
that modification to the repository.

One potentially surprising aspect of the fact that
@code{cvs tag} operates on the repository is that you
are tagging the checked-in revisions, which may differ
from locally modified files in your working directory.
If you want to avoid doing this by mistake, specify the
@samp{-c} option to @code{cvs tag}.  If there are any
locally modified files, @sc{cvs} will abort with an
error before it tags any files:

@example
$ cvs tag -c rel-0-4
cvs tag: backend.c is locally modified
cvs [tag aborted]: correct the above errors first!
@end example

@node Tagging by date/tag
@section Specifying what to tag by date or revision
@cindex rtag (subcommand)

The @code{cvs rtag} command tags the repository as of a
certain date or time (or can be used to tag the latest
revision).  @code{rtag} works directly on the
repository contents (it requires no prior checkout and
does not look for a working directory).

The following options specify which date or revision to
tag.  See @ref{Common options}, for a complete
description of them.

@table @code
@item -D @var{date}
Tag the most recent revision no later than @var{date}.

@item -f
Only useful with the @samp{-D @var{date}} or @samp{-r @var{tag}}
flags.  If no matching revision is found, use the most
recent revision (instead of ignoring the file).

@item -r @var{tag}
Only tag those files that contain existing tag @var{tag}.
@end table

The @code{cvs tag} command also allows one to specify
files by revision or date, using the same @samp{-r},
@samp{-D}, and @samp{-f} options.  However, this
feature is probably not what you want.  The reason is
that @code{cvs tag} chooses which files to tag based on
the files that exist in the working directory, rather
than the files which existed as of the given tag/date.
Therefore, you are generally better off using @code{cvs
rtag}.  The exceptions might be cases like:

@example
cvs tag -r 1.4 backend.c
@end example

@node Modifying tags
@section Deleting, moving, and renaming tags

@c Also see:
@c  "How do I move or rename a magic branch tag?"
@c in the FAQ (I think the issues it talks about still
@c apply, but this could use some sanity.sh work).

Normally one does not modify tags.  They exist in order
to record the history of the repository and so deleting
them or changing their meaning would, generally, not be
what you want.

However, there might be cases in which one uses a tag
temporarily or accidentally puts one in the wrong
place.  Therefore, one might delete, move, or rename a
tag.

@noindent
@strong{WARNING:  The commands in this section are
dangerous; they permanently discard historical
information and it can be difficult or impossible to
recover from errors.  If you are a @sc{cvs}
administrator, you may consider restricting these
commands with the @file{taginfo} file (@pxref{taginfo}).}

@cindex Deleting tags
@cindex Deleting branch tags
@cindex Removing tags
@cindex Removing branch tags
@cindex Tags, deleting
@cindex Branch tags, deleting
To delete a tag, specify the @samp{-d} option to either
@code{cvs tag} or @code{cvs rtag}.  For example:

@example
cvs rtag -d rel-0-4 tc
@end example

@noindent
deletes the non-branch tag @code{rel-0-4} from the module @code{tc}.
In the event that branch tags are encountered within the repository
with the given name, a warning message will be issued and the branch 
tag will not be deleted.  If you are absolutely certain you know what
you are doing, the @code{-B} option may be specified to allow deletion
of branch tags.  In that case, any non-branch tags encountered will
trigger warnings and will not be deleted.

@noindent
@strong{WARNING:  Moving branch tags is very dangerous!  If you think
you need the @code{-B} option, think again and ask your @sc{cvs}
administrator about it (if that isn't you).  There is almost certainly
another way to accomplish what you want to accomplish.}

@cindex Moving tags
@cindex Moving branch tags
@cindex Tags, moving
@cindex Branch tags, moving
When we say @dfn{move} a tag, we mean to make the same
name point to different revisions.  For example, the
@code{stable} tag may currently point to revision 1.4
of @file{backend.c} and perhaps we want to make it
point to revision 1.6.  To move a non-branch tag, specify the
@samp{-F} option to either @code{cvs tag} or @code{cvs
rtag}.  For example, the task just mentioned might be
accomplished as:

@example
cvs tag -r 1.6 -F stable backend.c
@end example

@noindent
If any branch tags are encountered in the repository 
with the given name, a warning is issued and the branch
tag is not disturbed.  If you are absolutely certain you
wish to move the branch tag, the @code{-B} option may be specified.
In that case, non-branch tags encountered with the given
name are ignored with a warning message.

@noindent
@strong{WARNING:  Moving branch tags is very dangerous!  If you think you
need the @code{-B} option, think again and ask your @sc{cvs}
administrator about it (if that isn't you).  There is almost certainly
another way to accomplish what you want to accomplish.}

@cindex Renaming tags
@cindex Tags, renaming
When we say @dfn{rename} a tag, we mean to make a
different name point to the same revisions as the old
tag.  For example, one may have misspelled the tag name
and want to correct it (hopefully before others are
relying on the old spelling).  To rename a tag, first
create a new tag using the @samp{-r} option to
@code{cvs rtag}, and then delete the old name.  (Caution:
this method will not work with branch tags.) 
This leaves the new tag on exactly the 
same files as the old tag.  For example:

@example
cvs rtag -r old-name-0-4 rel-0-4 tc
cvs rtag -d old-name-0-4 tc
@end example

@node Tagging add/remove
@section Tagging and adding and removing files

The subject of exactly how tagging interacts with
adding and removing files is somewhat obscure; for the
most part @sc{cvs} will keep track of whether files
exist or not without too much fussing.  By default,
tags are applied to only files which have a revision
corresponding to what is being tagged.  Files which did
not exist yet, or which were already removed, simply
omit the tag, and @sc{cvs} knows to treat the absence
of a tag as meaning that the file didn't exist as of
that tag.

However, this can lose a small amount of information.
For example, suppose a file was added and then removed.
Then, if the tag is missing for that file, there is no
way to know whether the tag refers to the time before
the file was added, or the time after it was removed.
If you specify the @samp{-r} option to @code{cvs rtag},
then @sc{cvs} tags the files which have been removed,
and thereby avoids this problem.  For example, one
might specify @code{-r HEAD} to tag the head.

On the subject of adding and removing files, the
@code{cvs rtag} command has a @samp{-a} option which
means to clear the tag from removed files that would
not otherwise be tagged.  For example, one might
specify this option in conjunction with @samp{-F} when
moving a tag.  If one moved a tag without @samp{-a},
then the tag in the removed files might still refer to
the old revision, rather than reflecting the fact that
the file had been removed.  I don't think this is
necessary if @samp{-r} is specified, as noted above.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Sticky tags
@section Sticky tags
@cindex Sticky tags
@cindex Tags, sticky

@c A somewhat related issue is per-directory sticky
@c tags (see comment at CVS/Tag in node Working
@c directory storage); we probably want to say
@c something like "you can set a sticky tag for only
@c some files, but you don't want to" or some such.

Sometimes a working copy's revision has extra data
associated with it, for example it might be on a branch
(@pxref{Branching and merging}), or restricted to
versions prior to a certain date by @samp{checkout -D}
or @samp{update -D}.  Because this data persists --
that is, it applies to subsequent commands in the
working copy -- we refer to it as @dfn{sticky}.

Most of the time, stickiness is an obscure aspect of
@sc{cvs} that you don't need to think about.  However,
even if you don't want to use the feature, you may need
to know @emph{something} about sticky tags (for
example, how to avoid them!).

You can use the @code{status} command to see if any
sticky tags or dates are set:

@example
$ cvs status driver.c
===================================================================
File: driver.c          Status: Up-to-date

    Version:            1.7.2.1 Sat Dec  5 19:35:03 1992
    RCS Version:        1.7.2.1 /u/cvsroot/yoyodyne/tc/driver.c,v
    Sticky Tag:         rel-1-0-patches (branch: 1.7.2)
    Sticky Date:        (none)
    Sticky Options:     (none)

@end example

@cindex Resetting sticky tags
@cindex Sticky tags, resetting
@cindex Deleting sticky tags
The sticky tags will remain on your working files until
you delete them with @samp{cvs update -A}.  The
@samp{-A} option merges local changes into the version of the
file from the head of the trunk, removing any sticky tags,
dates, or options (other than sticky @samp{-k} options on locally
modified files).  See @ref{update} for more on the operation
of @code{cvs update}.

@cindex Sticky date
The most common use of sticky tags is to identify which
branch one is working on, as described in
@ref{Accessing branches}.  However, non-branch
sticky tags have uses as well.  For example,
suppose that you want to avoid updating your working
directory, to isolate yourself from possibly
destabilizing changes other people are making.  You
can, of course, just refrain from running @code{cvs
update}.  But if you want to avoid updating only a
portion of a larger tree, then sticky tags can help.
If you check out a certain revision (such as 1.4) it
will become sticky.  Subsequent @code{cvs update}
commands will
not retrieve the latest revision until you reset the
tag with @code{cvs update -A}.  Likewise, use of the
@samp{-D} option to @code{update} or @code{checkout}
sets a @dfn{sticky date}, which, similarly, causes that
date to be used for future retrievals.

People often want to retrieve an old version of
a file without setting a sticky tag.  This can
be done with the @samp{-p} option to @code{checkout} or
@code{update}, which sends the contents of the file to
standard output.  For example:
@example
$ cvs update -p -r 1.1 file1 >file1
===================================================================
Checking out file1
RCS:  /tmp/cvs-sanity/cvsroot/first-dir/Attic/file1,v
VERS: 1.1
***************
$
@end example

However, this isn't the easiest way, if you are asking
how to undo a previous checkin (in this example, put
@file{file1} back to the way it was as of revision
1.1).  In that case you are better off using the
@samp{-j} option to @code{update}; for further
discussion see @ref{Merging two revisions}.

@c ---------------------------------------------------------------------
@node Branching and merging
@chapter Branching and merging
@cindex Branching
@cindex Merging
@cindex Copying changes
@cindex Main trunk and branches
@cindex Revision tree, making branches
@cindex Branches, copying changes between
@cindex Changes, copying between branches
@cindex Modifications, copying between branches

@sc{cvs} allows you to isolate changes onto a separate
line of development, known as a @dfn{branch}.  When you
change files on a branch, those changes do not appear
on the main trunk or other branches.

Later you can move changes from one branch to another
branch (or the main trunk) by @dfn{merging}.  Merging
involves first running @code{cvs update -j}, to merge
the changes into the working directory.
You can then commit that revision, and thus effectively
copy the changes onto another branch.

@menu
* Branches motivation::         What branches are good for
* Creating a branch::           Creating a branch
* Accessing branches::          Checking out and updating branches
* Branches and revisions::      Branches are reflected in revision numbers
* Magic branch numbers::        Magic branch numbers
* Merging a branch::            Merging an entire branch
* Merging more than once::      Merging from a branch several times
* Merging two revisions::       Merging differences between two revisions
* Merging adds and removals::   What if files are added or removed?
* Merging and keywords::        Avoiding conflicts due to keyword substitution
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Branches motivation
@section What branches are good for
@cindex Branches motivation
@cindex What branches are good for
@cindex Motivation for branches

@c FIXME: this node mentions one way to use branches,
@c but it is by no means the only way.  For example,
@c the technique of committing a new feature on a branch,
@c until it is ready for the main trunk.  The whole
@c thing is generally speaking more akin to the
@c "Revision management" node although it isn't clear to
@c me whether policy matters should be centralized or
@c distributed throughout the relevant sections.
Suppose that release 1.0 of tc has been made.  You are continuing to
develop tc, planning to create release 1.1 in a couple of months.  After a
while your customers start to complain about a fatal bug.  You check
out release 1.0 (@pxref{Tags}) and find the bug
(which turns out to have a trivial fix).  However, the current revision
of the sources are in a state of flux and are not expected to be stable
for at least another month.  There is no way to make a
bug fix release based on the newest sources.

The thing to do in a situation like this is to create a @dfn{branch} on
the revision trees for all the files that make up
release 1.0 of tc.  You can then make
modifications to the branch without disturbing the main trunk.  When the
modifications are finished you can elect to either incorporate them on
the main trunk, or leave them on the branch.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Creating a branch
@section Creating a branch
@cindex Creating a branch
@cindex Branch, creating a
@cindex tag, creating a branch using
@cindex rtag, creating a branch using

You can create a branch with @code{tag -b}; for
example, assuming you're in a working copy:

@example
$ cvs tag -b rel-1-0-patches
@end example

@c FIXME: we should be more explicit about the value of
@c having a tag on the branchpoint.  For example
@c "cvs tag rel-1-0-patches-branchpoint" before
@c the "cvs tag -b".  This points out that
@c rel-1-0-patches is a pretty awkward name for
@c this example (more so than for the rtag example
@c below).

This splits off a branch based on the current revisions
in the working copy, assigning that branch the name
@samp{rel-1-0-patches}.

It is important to understand that branches get created
in the repository, not in the working copy.  Creating a
branch based on current revisions, as the above example
does, will @emph{not} automatically switch the working
copy to be on the new branch.  For information on how
to do that, see @ref{Accessing branches}.

You can also create a branch without reference to any
working copy, by using @code{rtag}:

@example
$ cvs rtag -b -r rel-1-0 rel-1-0-patches tc
@end example

@samp{-r rel-1-0} says that this branch should be
rooted at the revision that
corresponds to the tag @samp{rel-1-0}.  It need not
be the most recent revision -- it's often useful to
split a branch off an old revision (for example, when
fixing a bug in a past release otherwise known to be
stable).

As with @samp{tag}, the @samp{-b} flag tells
@code{rtag} to create a branch (rather than just a
symbolic revision name).  Note that the numeric
revision number that matches @samp{rel-1-0} will
probably be different from file to file.

So, the full effect of the command is to create a new
branch -- named @samp{rel-1-0-patches} -- in module
@samp{tc}, rooted in the revision tree at the point tagged
by @samp{rel-1-0}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Accessing branches
@section Accessing branches
@cindex Check out a branch
@cindex Retrieve a branch
@cindex Access a branch
@cindex Identifying a branch
@cindex Branch, check out
@cindex Branch, retrieving
@cindex Branch, accessing
@cindex Branch, identifying

You can retrieve a branch in one of two ways: by
checking it out fresh from the repository, or by
switching an existing working copy over to the branch.

To check out a branch from the repository, invoke
@samp{checkout} with the @samp{-r} flag, followed by
the tag name of the branch (@pxref{Creating a branch}):

@example
$ cvs checkout -r rel-1-0-patches tc
@end example

Or, if you already have a working copy, you can switch
it to a given branch with @samp{update -r}:

@example
$ cvs update -r rel-1-0-patches tc
@end example

@noindent
or equivalently:

@example
$ cd tc
$ cvs update -r rel-1-0-patches
@end example

It does not matter if the working copy was originally
on the main trunk or on some other branch -- the above
command will switch it to the named branch.  And
similarly to a regular @samp{update} command,
@samp{update -r} merges any changes you have made,
notifying you of conflicts where they occur.

Once you have a working copy tied to a particular
branch, it remains there until you tell it otherwise.
This means that changes checked in from the working
copy will add new revisions on that branch, while
leaving the main trunk and other branches unaffected.

@cindex Branches, sticky
To find out what branch a working copy is on, you can
use the @samp{status} command.  In its output, look for
the field named @samp{Sticky tag} (@pxref{Sticky tags})
-- that's @sc{cvs}'s way of telling you the branch, if
any, of the current working files:

@example
$ cvs status -v driver.c backend.c
===================================================================
File: driver.c          Status: Up-to-date

    Version:            1.7     Sat Dec  5 18:25:54 1992
    RCS Version:        1.7     /u/cvsroot/yoyodyne/tc/driver.c,v
    Sticky Tag:         rel-1-0-patches (branch: 1.7.2)
    Sticky Date:        (none)
    Sticky Options:     (none)

    Existing Tags:
        rel-1-0-patches             (branch: 1.7.2)
        rel-1-0                     (revision: 1.7)

===================================================================
File: backend.c         Status: Up-to-date

    Version:            1.4     Tue Dec  1 14:39:01 1992
    RCS Version:        1.4     /u/cvsroot/yoyodyne/tc/backend.c,v
    Sticky Tag:         rel-1-0-patches (branch: 1.4.2)
    Sticky Date:        (none)
    Sticky Options:     (none)

    Existing Tags:
        rel-1-0-patches             (branch: 1.4.2)
        rel-1-0                     (revision: 1.4)
        rel-0-4                     (revision: 1.4)

@end example

Don't be confused by the fact that the branch numbers
for each file are different (@samp{1.7.2} and
@samp{1.4.2} respectively).  The branch tag is the
same, @samp{rel-1-0-patches}, and the files are
indeed on the same branch.  The numbers simply reflect
the point in each file's revision history at which the
branch was made.  In the above example, one can deduce
that @samp{driver.c} had been through more changes than
@samp{backend.c} before this branch was created.

See @ref{Branches and revisions} for details about how
branch numbers are constructed.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Branches and revisions
@section Branches and revisions
@cindex Branch number
@cindex Number, branch
@cindex Revision numbers (branches)

Ordinarily, a file's revision history is a linear
series of increments (@pxref{Revision numbers}):

@example
       +-----+    +-----+    +-----+    +-----+    +-----+
       ! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !
       +-----+    +-----+    +-----+    +-----+    +-----+
@end example

However, @sc{cvs} is not limited to linear development.  The
@dfn{revision tree} can be split into @dfn{branches},
where each branch is a self-maintained line of
development.  Changes made on one branch can easily be
moved back to the main trunk.

Each branch has a @dfn{branch number}, consisting of an
odd number of period-separated decimal integers.  The
branch number is created by appending an integer to the
revision number where the corresponding branch forked
off.  Having branch numbers allows more than one branch
to be forked off from a certain revision.

@need 3500
All revisions on a branch have revision numbers formed
by appending an ordinal number to the branch number.
The following figure illustrates branching with an
example.

@example
@c This example used to have a 1.2.2.4 revision, which
@c might help clarify that development can continue on
@c 1.2.2.  Might be worth reinstating if it can be done
@c without overfull hboxes.
@group
                                                      +-------------+
                           Branch 1.2.2.3.2 ->        ! 1.2.2.3.2.1 !
                                                    / +-------------+
                                                   /
                                                  /
                 +---------+    +---------+    +---------+
Branch 1.2.2 -> _! 1.2.2.1 !----! 1.2.2.2 !----! 1.2.2.3 !
               / +---------+    +---------+    +---------+
              /
             /
+-----+    +-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !  <- The main trunk
+-----+    +-----+    +-----+    +-----+    +-----+
                !
                !
                !   +---------+    +---------+    +---------+
Branch 1.2.4 -> +---! 1.2.4.1 !----! 1.2.4.2 !----! 1.2.4.3 !
                    +---------+    +---------+    +---------+

@end group
@end example

@c --   However, at least for me the figure is not enough.  I suggest more
@c --   text to accompany it.  "A picture is worth a thousand words", so you
@c --   have to make sure the reader notices the couple of hundred words
@c --   *you* had in mind more than the others!

@c --   Why an even number of segments?  This section implies that this is
@c --   how the main trunk is distinguished from branch roots, but you never
@c --   explicitly say that this is the purpose of the [by itself rather
@c --   surprising] restriction to an even number of segments.

The exact details of how the branch number is
constructed is not something you normally need to be
concerned about, but here is how it works: When
@sc{cvs} creates a branch number it picks the first
unused even integer, starting with 2.  So when you want
to create a branch from revision 6.4 it will be
numbered 6.4.2.  All branch numbers ending in a zero
(such as 6.4.0) are used internally by @sc{cvs}
(@pxref{Magic branch numbers}).  The branch 1.1.1 has a
special meaning.  @xref{Tracking sources}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Magic branch numbers
@section Magic branch numbers

@c Want xref to here from "log"?

This section describes a @sc{cvs} feature called
@dfn{magic branches}.  For most purposes, you need not
worry about magic branches; @sc{cvs} handles them for
you.  However, they are visible to you in certain
circumstances, so it may be useful to have some idea of
how it works.

Externally, branch numbers consist of an odd number of
dot-separated decimal integers.  @xref{Revision
numbers}.  That is not the whole truth, however.  For
efficiency reasons @sc{cvs} sometimes inserts an extra 0
in the second rightmost position (1.2.4 becomes
1.2.0.4, 8.9.10.11.12 becomes 8.9.10.11.0.12 and so
on).

@sc{cvs} does a pretty good job at hiding these so
called magic branches, but in a few places the hiding
is incomplete:

@itemize @bullet
@ignore
@c This is in ignore as I'm taking their word for it,
@c that this was fixed
@c a long time ago.  But before deleting this
@c entirely, I'd rather verify it (and add a test
@c case to the testsuite).
@item
The magic branch can appear in the output from
@code{cvs status} in vanilla @sc{cvs} 1.3.  This is
fixed in @sc{cvs} 1.3-s2.

@end ignore
@item
The magic branch number appears in the output from
@code{cvs log}.
@c What output should appear instead?

@item
You cannot specify a symbolic branch name to @code{cvs
admin}.

@end itemize

@c Can CVS do this automatically the first time
@c you check something in to that branch?  Should
@c it?
You can use the @code{admin} command to reassign a
symbolic name to a branch the way @sc{rcs} expects it
to be.  If @code{R4patches} is assigned to the branch
1.4.2 (magic branch number 1.4.0.2) in file
@file{numbers.c} you can do this:

@example
$ cvs admin -NR4patches:1.4.2 numbers.c
@end example

It only works if at least one revision is already
committed on the branch.  Be very careful so that you
do not assign the tag to the wrong number.  (There is
no way to see how the tag was assigned yesterday).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Merging a branch
@section Merging an entire branch
@cindex Merging a branch
@cindex -j (merging branches)

You can merge changes made on a branch into your working copy by giving
the @samp{-j @var{branchname}} flag to the @code{update} subcommand.  With one
@samp{-j @var{branchname}} option it merges the changes made between the
greatest common ancestor (GCA) of the branch and the destination revision (in
the simple case below the GCA is the point where the branch forked) and the
newest revision on that branch into your working copy.

@cindex Join
The @samp{-j} stands for ``join''.

@cindex Branch merge example
@cindex Example, branch merge
@cindex Merge, branch example
Consider this revision tree:

@example
+-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !      <- The main trunk
+-----+    +-----+    +-----+    +-----+
                !
                !
                !   +---------+    +---------+
Branch R1fix -> +---! 1.2.2.1 !----! 1.2.2.2 !
                    +---------+    +---------+
@end example

@noindent
The branch 1.2.2 has been given the tag (symbolic name) @samp{R1fix}.  The
following example assumes that the module @samp{mod} contains only one
file, @file{m.c}.

@example
$ cvs checkout mod               # @r{Retrieve the latest revision, 1.4}

$ cvs update -j R1fix m.c        # @r{Merge all changes made on the branch,}
                                 # @r{i.e. the changes between revision 1.2}
                                 # @r{and 1.2.2.2, into your working copy}
                                 # @r{of the file.}

$ cvs commit -m "Included R1fix" # @r{Create revision 1.5.}
@end example

A conflict can result from a merge operation.  If that
happens, you should resolve it before committing the
new revision.  @xref{Conflicts example}.

If your source files contain keywords (@pxref{Keyword substitution}),
you might be getting more conflicts than strictly necessary.  See
@ref{Merging and keywords}, for information on how to avoid this.

The @code{checkout} command also supports the @samp{-j @var{branchname}} flag.  The
same effect as above could be achieved with this:

@example
$ cvs checkout -j R1fix mod
$ cvs commit -m "Included R1fix"
@end example

It should be noted that @code{update -j @var{tagname}} will also work but may
not produce the desired result.  @xref{Merging adds and removals}, for more.

@node Merging more than once
@section Merging from a branch several times

Continuing our example, the revision tree now looks
like this:

@example
+-----+    +-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !   <- The main trunk
+-----+    +-----+    +-----+    +-----+    +-----+
                !                           *
                !                          *
                !   +---------+    +---------+
Branch R1fix -> +---! 1.2.2.1 !----! 1.2.2.2 !
                    +---------+    +---------+
@end example

@noindent
where the starred line represents the merge from the
@samp{R1fix} branch to the main trunk, as just
discussed.

Now suppose that development continues on the
@samp{R1fix} branch:

@example
+-----+    +-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !   <- The main trunk
+-----+    +-----+    +-----+    +-----+    +-----+
                !                           *
                !                          *
                !   +---------+    +---------+    +---------+
Branch R1fix -> +---! 1.2.2.1 !----! 1.2.2.2 !----! 1.2.2.3 !
                    +---------+    +---------+    +---------+
@end example

@noindent
and then you want to merge those new changes onto the
main trunk.  If you just use the @code{cvs update -j
R1fix m.c} command again, @sc{cvs} will attempt to
merge again the changes which you have already merged,
which can have undesirable side effects.

So instead you need to specify that you only want to
merge the changes on the branch which have not yet been
merged into the trunk.  To do that you specify two
@samp{-j} options, and @sc{cvs} merges the changes from
the first revision to the second revision.  For
example, in this case the simplest way would be

@example
cvs update -j 1.2.2.2 -j R1fix m.c    # @r{Merge changes from 1.2.2.2 to the}
                                      # @r{head of the R1fix branch}
@end example

The problem with this is that you need to specify the
1.2.2.2 revision manually.  A slightly better approach
might be to use the date the last merge was done:

@example
cvs update -j R1fix:yesterday -j R1fix m.c
@end example

Better yet, tag the R1fix branch after every merge into
the trunk, and then use that tag for subsequent merges:

@example
cvs update -j merged_from_R1fix_to_trunk -j R1fix m.c
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Merging two revisions
@section Merging differences between any two revisions
@cindex Merging two revisions
@cindex Revisions, merging differences between
@cindex Differences, merging

With two @samp{-j @var{revision}} flags, the @code{update}
(and @code{checkout}) command can merge the differences
between any two revisions into your working file.

@cindex Undoing a change
@cindex Removing a change
@example
$ cvs update -j 1.5 -j 1.3 backend.c
@end example

@noindent
will undo all changes made between revision
1.3 and 1.5.  Note the order of the revisions!

If you try to use this option when operating on
multiple files, remember that the numeric revisions will
probably be very different between the various files.
You almost always use symbolic
tags rather than revision numbers when operating on
multiple files.

@cindex Restoring old version of removed file
@cindex Resurrecting old version of dead file
Specifying two @samp{-j} options can also undo file
removals or additions.  For example, suppose you have
a file
named @file{file1} which existed as revision 1.1, and
you then removed it (thus adding a dead revision 1.2).
Now suppose you want to add it again, with the same
contents it had previously.  Here is how to do it:

@example
$ cvs update -j 1.2 -j 1.1 file1
U file1
$ cvs commit -m test
Checking in file1;
/tmp/cvs-sanity/cvsroot/first-dir/file1,v  <--  file1
new revision: 1.3; previous revision: 1.2
done
$
@end example

@node Merging adds and removals
@section Merging can add or remove files

If the changes which you are merging involve removing
or adding some files, @code{update -j} will reflect
such additions or removals.

@c FIXME: This example needs a lot more explanation.
@c We also need other examples for some of the other
@c cases (not all--there are too many--as long as we present a
@c coherent general principle).
For example:
@example
cvs update -A
touch a b c
cvs add a b c ; cvs ci -m "added" a b c
cvs tag -b branchtag
cvs update -r branchtag
touch d ; cvs add d
rm a ; cvs rm a
cvs ci -m "added d, removed a"
cvs update -A
cvs update -jbranchtag
@end example

After these commands are executed and a @samp{cvs commit} is done,
file @file{a} will be removed and file @file{d} added in the main branch.
@c (which was determined by trying it)

Note that using a single static tag (@samp{-j @var{tagname}})
rather than a dynamic tag (@samp{-j @var{branchname}}) to merge
changes from a branch will usually not remove files which were removed on the
branch since @sc{cvs} does not automatically add static tags to dead revisions.
The exception to this rule occurs when
a static tag has been attached to a dead revision manually.  Use the branch tag
to merge all changes from the branch or use two static tags as merge endpoints
to be sure that all intended changes are propagated in the merge.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Merging and keywords
@section Merging and keywords
@cindex Merging, and keyword substitution
@cindex Keyword substitution, and merging
@cindex -j (merging branches), and keyword substitution
@cindex -kk, to avoid conflicts during a merge

If you merge files containing keywords (@pxref{Keyword
substitution}), you will normally get numerous
conflicts during the merge, because the keywords are
expanded differently in the revisions which you are
merging.

Therefore, you will often want to specify the
@samp{-kk} (@pxref{Substitution modes}) switch to the
merge command line.  By substituting just the name of
the keyword, not the expanded value of that keyword,
this option ensures that the revisions which you are
merging will be the same as each other, and avoid
spurious conflicts.

For example, suppose you have a file like this:

@example
       +---------+
      _! 1.1.2.1 !   <-  br1
     / +---------+
    /
   /
+-----+    +-----+
! 1.1 !----! 1.2 !
+-----+    +-----+
@end example

@noindent
and your working directory is currently on the trunk
(revision 1.2).  Then you might get the following
results from a merge:

@example
$ cat file1
key $@splitrcskeyword{Revision}: 1.2 $
. . .
$ cvs update -j br1
U file1
RCS file: /cvsroot/first-dir/file1,v
retrieving revision 1.1
retrieving revision 1.1.2.1
Merging differences between 1.1 and 1.1.2.1 into file1
rcsmerge: warning: conflicts during merge
$ cat file1
@asis{}<<<<<<< file1
key $@splitrcskeyword{Revision}: 1.2 $
@asis{}=======
key $@splitrcskeyword{Revision}: 1.1.2.1 $
@asis{}>>>>>>> 1.1.2.1
. . .
@end example

What happened was that the merge tried to merge the
differences between 1.1 and 1.1.2.1 into your working
directory.  So, since the keyword changed from
@code{Revision: 1.1} to @code{Revision: 1.1.2.1},
@sc{cvs} tried to merge that change into your working
directory, which conflicted with the fact that your
working directory had contained @code{Revision: 1.2}.

Here is what happens if you had used @samp{-kk}:

@example
$ cat file1
key $@splitrcskeyword{Revision}: 1.2 $
. . .
$ cvs update -kk -j br1
U file1
RCS file: /cvsroot/first-dir/file1,v
retrieving revision 1.1
retrieving revision 1.1.2.1
Merging differences between 1.1 and 1.1.2.1 into file1
$ cat file1
key $@splitrcskeyword{Revision}$
. . .
@end example

What is going on here is that revision 1.1 and 1.1.2.1
both expand as plain @code{Revision}, and therefore
merging the changes between them into the working
directory need not change anything.  Therefore, there
is no conflict.

There is, however, one major caveat with using
@samp{-kk} on merges.  Namely, it overrides whatever
keyword expansion mode @sc{cvs} would normally have
used.  In particular, this is a problem if the mode had
been @samp{-kb} for a binary file.  Therefore, if your
repository contains binary files, you will need to deal
with the conflicts rather than using @samp{-kk}.

@ignore
The following seems rather confusing, possibly buggy,
and in general, in need of much more thought before it
is a recommended technique.  For one thing, does it
apply on Windows as well as on Unix?

Unchanged binary files will undergo the same keyword substitution
but will not be checked in on a subsequent
@code{cvs commit}.  Be aware that binary files containing keyword
strings which are present in or below the working directory
will most likely remain corrupt until repaired, however.  A simple 
@code{cvs update -A} is sufficient to fix these otherwise unaltered binary files
if the merge is being done to the main branch but
this must be done after the merge has been committed or the merge itself
will be lost.

For Example:
@example
cvs update -Akk -jbranchtag
cvs commit
cvs update -A
@end example

@noindent
will update the current directory from the main trunk of the
repository, substituting the base keyword strings for keywords,
and merge changes made on the branch @samp{branchtag} into the new
work files, performing the same keyword substitution on that file set before
comparing the two sets.  The final @code{cvs update -A} will restore any
corrupted binary files as well as resetting the sticky @samp{-kk} tags which
were present on the files in and below the working directory.
Unfortunately, this doesn't work as well with an arbitrary branch tag, as the
@samp{-r @var{branchtag}} switch does not reset the sticky @samp{-kk}
switches attached to the working files as @samp{-A} does.  The workaround
for this is to release the working directory after the merge has been
committed and check it out again.
@end ignore

As a result of using @samp{-kk} during the merge, each file examined by the
update will have @samp{-kk} set as sticky options.  Running @code{update -A}
will clear the sticky options on unmodified files, but it will not clear
the sticky options on modified files.  To get back to the default keyword
substitution for modified files, you must commit the results of the merge
and then run @code{update -A}.

@c ---------------------------------------------------------------------
@node Recursive behavior
@chapter Recursive behavior
@cindex Recursive (directory descending)
@cindex Directory, descending
@cindex Descending directories
@cindex Subdirectories

Almost all of the subcommands of @sc{cvs} work
recursively when you specify a directory as an
argument.  For instance, consider this directory
structure:

@example
      @code{$HOME}
        |
        +--@t{tc}
        |   |
            +--@t{CVS}
            |      (internal @sc{cvs} files)
            +--@t{Makefile}
            +--@t{backend.c}
            +--@t{driver.c}
            +--@t{frontend.c}
            +--@t{parser.c}
            +--@t{man}
            |    |
            |    +--@t{CVS}
            |    |  (internal @sc{cvs} files)
            |    +--@t{tc.1}
            |
            +--@t{testing}
                 |
                 +--@t{CVS}
                 |  (internal @sc{cvs} files)
                 +--@t{testpgm.t}
                 +--@t{test2.t}
@end example

@noindent
If @file{tc} is the current working directory, the
following is true:

@itemize @bullet
@item
@samp{cvs update testing} is equivalent to

@example
cvs update testing/testpgm.t testing/test2.t
@end example

@item
@samp{cvs update testing man} updates all files in the
subdirectories

@item
@samp{cvs update .} or just @samp{cvs update} updates
all files in the @code{tc} directory
@end itemize

If no arguments are given to @code{update} it will
update all files in the current working directory and
all its subdirectories.  In other words, @file{.} is a
default argument to @code{update}.  This is also true
for most of the @sc{cvs} subcommands, not only the
@code{update} command.

The recursive behavior of the @sc{cvs} subcommands can be
turned off with the @samp{-l} option.
Conversely, the @samp{-R} option can be used to force recursion if
@samp{-l} is specified in @file{~/.cvsrc} (@pxref{~/.cvsrc}).

@example
$ cvs update -l         # @r{Don't update files in subdirectories}
@end example

@c ---------------------------------------------------------------------
@node Adding and removing
@chapter Adding, removing, and renaming files and directories

In the course of a project, one will often add new
files.  Likewise with removing or renaming, or with
directories.  The general concept to keep in mind in
all these cases is that instead of making an
irreversible change you want @sc{cvs} to record the
fact that a change has taken place, just as with
modifying an existing file.  The exact mechanisms to do
this in @sc{cvs} vary depending on the situation.

@menu
* Adding files::                Adding files
* Removing files::              Removing files
* Removing directories::        Removing directories
* Moving files::                Moving and renaming files
* Moving directories::          Moving and renaming directories
@end menu

@node Adding files
@section Adding files to a directory
@cindex Adding files

To add a new file to a directory, follow these steps.

@itemize @bullet
@item
You must have a working copy of the directory.
@xref{Getting the source}.

@item
Create the new file inside your working copy of the directory.

@item
Use @samp{cvs add @var{filename}} to tell @sc{cvs} that you
want to version control the file.  If the file contains
binary data, specify @samp{-kb} (@pxref{Binary files}).

@item
Use @samp{cvs commit @var{filename}} to actually check
in the file into the repository.  Other developers
cannot see the file until you perform this step.
@end itemize

You can also use the @code{add} command to add a new
directory.
@c FIXCVS and/or FIXME: Adding a directory doesn't
@c require the commit step.  This probably can be
@c considered a CVS bug, but it is possible we should
@c warn people since this behavior probably won't be
@c changing right away.

Unlike most other commands, the @code{add} command is
not recursive.  You have to explicitly name files and
directories that you wish to add to the repository.
However, each directory will need to be added
separately before you will be able to add new files
to those directories.

@example
$ mkdir -p foo/bar
$ cp ~/myfile foo/bar/myfile
$ cvs add foo foo/bar
$ cvs add foo/bar/myfile
@end example

@cindex add (subcommand)
@deffn Command {cvs add} [@code{-k} kflag] [@code{-m} message] files @dots{}

Schedule @var{files} to be added to the repository.
The files or directories specified with @code{add} must
already exist in the current directory.  To add a whole
new directory hierarchy to the source repository (for
example, files received from a third-party vendor), use
the @code{import} command instead.  @xref{import}.

The added files are not placed in the source repository
until you use @code{commit} to make the change
permanent.  Doing an @code{add} on a file that was
removed with the @code{remove} command will undo the
effect of the @code{remove}, unless a @code{commit}
command intervened.  @xref{Removing files}, for an
example.

The @samp{-k} option specifies the default way that
this file will be checked out; for more information see
@ref{Substitution modes}.

@c As noted in BUGS, -m is broken client/server (Nov
@c 96).  Also see testsuite log2-* tests.
The @samp{-m} option specifies a description for the
file.  This description appears in the history log (if
it is enabled, @pxref{history file}).  It will also be
saved in the version history inside the repository when
the file is committed.  The @code{log} command displays
this description.  The description can be changed using
@samp{admin -t}.  @xref{admin}.  If you omit the
@samp{-m @var{description}} flag, an empty string will
be used.  You will not be prompted for a description.
@end deffn

For example, the following commands add the file
@file{backend.c} to the repository:

@c This example used to specify
@c     -m "Optimizer and code generation passes."
@c to the cvs add command, but that doesn't work
@c client/server (see log2 in sanity.sh).  Should fix CVS,
@c but also seems strange to document things which
@c don't work...
@example
$ cvs add backend.c
$ cvs commit -m "Early version. Not yet compilable." backend.c
@end example

When you add a file it is added only on the branch
which you are working on (@pxref{Branching and merging}).  You can
later merge the additions to another branch if you want
(@pxref{Merging adds and removals}).
@c Should we mention that earlier versions of CVS
@c lacked this feature (1.3) or implemented it in a buggy
@c way (well, 1.8 had many bugs in cvs update -j)?
@c Should we mention the bug/limitation regarding a
@c file being a regular file on one branch and a directory
@c on another?
@c FIXME: This needs an example, or several, here or
@c elsewhere, for it to make much sense.
@c Somewhere we need to discuss the aspects of death
@c support which don't involve branching, I guess.
@c Like the ability to re-create a release from a tag.

@c ---------------------------------------------------------------------
@node Removing files
@section Removing files
@cindex Removing files
@cindex Deleting files

@c FIXME: this node wants to be split into several
@c smaller nodes.  Could make these children of
@c "Adding and removing", probably (death support could
@c be its own section, for example, as could the
@c various bits about undoing mistakes in adding and
@c removing).
Directories change.  New files are added, and old files
disappear.  Still, you want to be able to retrieve an
exact copy of old releases.

Here is what you can do to remove a file,
but remain able to retrieve old revisions:

@itemize @bullet
@c FIXME: should probably be saying something about
@c having a working directory in the first place.
@item
Make sure that you have not made any uncommitted
modifications to the file.  @xref{Viewing differences},
for one way to do that.  You can also use the
@code{status} or @code{update} command.  If you remove
the file without committing your changes, you will of
course not be able to retrieve the file as it was
immediately before you deleted it.

@item
Remove the file from your working copy of the directory.
You can for instance use @code{rm}.

@item
Use @samp{cvs remove @var{filename}} to tell @sc{cvs} that
you really want to delete the file.

@item
Use @samp{cvs commit @var{filename}} to actually
perform the removal of the file from the repository.
@end itemize

@c FIXME: Somehow this should be linked in with a more
@c general discussion of death support.  I don't know
@c whether we want to use the term "death support" or
@c not (we can perhaps get by without it), but we do
@c need to discuss the "dead" state in "cvs log" and
@c related subjects.  The current discussion is
@c scattered around, and not xref'd to each other.
@c FIXME: I think this paragraph wants to be moved
@c later down, at least after the first example.
When you commit the removal of the file, @sc{cvs}
records the fact that the file no longer exists.  It is
possible for a file to exist on only some branches and
not on others, or to re-add another file with the same
name later.  @sc{cvs} will correctly create or not create
the file, based on the @samp{-r} and @samp{-D} options
specified to @code{checkout} or @code{update}.

@c FIXME: This style seems to clash with how we
@c document things in general.
@cindex Remove (subcommand)
@deffn Command {cvs remove} [options] files @dots{}

Schedule file(s) to be removed from the repository
(files which have not already been removed from the
working directory are not processed).  This command
does not actually remove the file from the repository
until you commit the removal.  For a full list of
options, see @ref{Invoking CVS}.
@end deffn

Here is an example of removing several files:

@example
$ cd test
$ rm *.c
$ cvs remove
cvs remove: Removing .
cvs remove: scheduling a.c for removal
cvs remove: scheduling b.c for removal
cvs remove: use 'cvs commit' to remove these files permanently
$ cvs ci -m "Removed unneeded files"
cvs commit: Examining .
cvs commit: Committing .
@end example

As a convenience you can remove the file and @code{cvs
remove} it in one step, by specifying the @samp{-f}
option.  For example, the above example could also be
done like this:

@example
$ cd test
$ cvs remove -f *.c
cvs remove: scheduling a.c for removal
cvs remove: scheduling b.c for removal
cvs remove: use 'cvs commit' to remove these files permanently
$ cvs ci -m "Removed unneeded files"
cvs commit: Examining .
cvs commit: Committing .
@end example

If you execute @code{remove} for a file, and then
change your mind before you commit, you can undo the
@code{remove} with an @code{add} command.
@ignore
@c is this worth saying or not?  Somehow it seems
@c confusing to me.
Of course,
since you have removed your copy of file in the working
directory, @sc{cvs} does not necessarily bring back the
contents of the file from right before you executed
@code{remove}; instead it gets the file from the
repository again.
@end ignore

@c FIXME: what if you change your mind after you commit
@c it?  (answer is also "cvs add" but we don't say that...).
@c We need some index entries for thinks like "undoing
@c removal" too.

@example
$ ls
CVS   ja.h  oj.c
$ rm oj.c
$ cvs remove oj.c
cvs remove: scheduling oj.c for removal
cvs remove: use 'cvs commit' to remove this file permanently
$ cvs add oj.c
U oj.c
cvs add: oj.c, version 1.1.1.1, resurrected
@end example

If you realize your mistake before you run the
@code{remove} command you can use @code{update} to
resurrect the file:

@example
$ rm oj.c
$ cvs update oj.c
cvs update: warning: oj.c was lost
U oj.c
@end example

When you remove a file it is removed only on the branch
which you are working on (@pxref{Branching and merging}).  You can
later merge the removals to another branch if you want
(@pxref{Merging adds and removals}).

@node Removing directories
@section Removing directories
@cindex Removing directories
@cindex Directories, removing

In concept, removing directories is somewhat similar to
removing files---you want the directory to not exist in
your current working directories, but you also want to
be able to retrieve old releases in which the directory
existed.

The way that you remove a directory is to remove all
the files in it.  You don't remove the directory
itself; there is no way to do that.
Instead you specify the @samp{-P} option to
@code{cvs update} or @code{cvs checkout},
which will cause @sc{cvs} to remove empty
directories from working directories.
(Note that @code{cvs export} always removes empty directories.)
Probably the
best way to do this is to always specify @samp{-P}; if
you want an empty directory then put a dummy file (for
example @file{.keepme}) in it to prevent @samp{-P} from
removing it.

@c I'd try to give a rationale for this, but I'm not
@c sure there is a particularly convincing one.  What
@c we would _like_ is for CVS to do a better job of version
@c controlling whether directories exist, to eliminate the
@c need for -P and so that a file can be a directory in
@c one revision and a regular file in another.
Note that @samp{-P} is implied by the @samp{-r} or @samp{-D}
options of @code{checkout}.  This way,
@sc{cvs} will be able to correctly create the directory
or not depending on whether the particular version you
are checking out contains any files in that directory.

@c ---------------------------------------------------------------------
@node Moving files
@section Moving and renaming files
@cindex Moving files
@cindex Renaming files
@cindex Files, moving

Moving files to a different directory or renaming them
is not difficult, but some of the ways in which this
works may be non-obvious.  (Moving or renaming a
directory is even harder.  @xref{Moving directories}.).

The examples below assume that the file @var{old} is renamed to
@var{new}.

@menu
* Outside::                     The normal way to Rename
* Inside::                      A tricky, alternative way
* Rename by copying::           Another tricky, alternative way
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Outside
@subsection The Normal way to Rename

@c More rename issues.  Not sure whether these are
@c worth documenting; I'm putting them here because
@c it seems to be as good a place as any to try to
@c set down the issues.
@c * "cvs annotate" will annotate either the new
@c file or the old file; it cannot annotate _each
@c line_ based on whether it was last changed in the
@c new or old file.  Unlike "cvs log", where the
@c consequences of having to select either the new
@c or old name seem fairly benign, this may be a
@c real advantage to having CVS know about renames
@c other than as a deletion and an addition.

The normal way to move a file is to copy @var{old} to
@var{new}, and then issue the normal @sc{cvs} commands
to remove @var{old} from the repository, and add
@var{new} to it.
@c The following sentence is not true: one must cd into
@c the directory to run "cvs add".
@c  (Both @var{old} and @var{new} could
@c contain relative paths, for example @file{foo/bar.c}).

@example
$ mv @var{old} @var{new}
$ cvs remove @var{old}
$ cvs add @var{new}
$ cvs commit -m "Renamed @var{old} to @var{new}" @var{old} @var{new}
@end example

This is the simplest way to move a file, it is not
error-prone, and it preserves the history of what was
done.  Note that to access the history of the file you
must specify the old or the new name, depending on what
portion of the history you are accessing.  For example,
@code{cvs log @var{old}} will give the log up until the
time of the rename.

When @var{new} is committed its revision numbers will
start again, usually at 1.1, so if that bothers you,
use the @samp{-r rev} option to commit.  For more
information see @ref{Assigning revisions}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Inside
@subsection Moving the history file

This method is more dangerous, since it involves moving
files inside the repository.  Read this entire section
before trying it out!

@example
$ cd $CVSROOT/@var{dir}
$ mv @var{old},v @var{new},v
@end example

@noindent
Advantages:

@itemize @bullet
@item
The log of changes is maintained intact.

@item
The revision numbers are not affected.
@end itemize

@noindent
Disadvantages:

@itemize @bullet
@item
Old releases cannot easily be fetched from the
repository.  (The file will show up as @var{new} even
in revisions from the time before it was renamed).

@item
There is no log information of when the file was renamed.

@item
Nasty things might happen if someone accesses the history file
while you are moving it.  Make sure no one else runs any of the @sc{cvs}
commands while you move it.
@end itemize

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Rename by copying
@subsection Copying the history file

This way also involves direct modifications to the
repository.  It is safe, but not without drawbacks.

@example
# @r{Copy the @sc{rcs} file inside the repository}
$ cd $CVSROOT/@var{dir}
$ cp @var{old},v @var{new},v
# @r{Remove the old file}
$ cd ~/@var{dir}
$ rm @var{old}
$ cvs remove @var{old}
$ cvs commit @var{old}
# @r{Remove all tags from @var{new}}
$ cvs update @var{new}
$ cvs log @var{new}             # @r{Remember the non-branch tag names}
$ cvs tag -d @var{tag1} @var{new}
$ cvs tag -d @var{tag2} @var{new}
@dots{}
@end example

By removing the tags you will be able to check out old
revisions.

@noindent
Advantages:

@itemize @bullet
@item
@c FIXME: Is this true about -D now that we have death
@c support?  See 5B.3 in the FAQ.
Checking out old revisions works correctly, as long as
you use @samp{-r@var{tag}} and not @samp{-D@var{date}}
to retrieve the revisions.

@item
The log of changes is maintained intact.

@item
The revision numbers are not affected.
@end itemize

@noindent
Disadvantages:

@itemize @bullet
@item
You cannot easily see the history of the file across the rename.

@ignore
@c Is this true?  I don't see how the revision numbers
@c _could_ start over, when new,v is just old,v with
@c the tags deleted.
@c If there is some need to reinstate this text,
@c it is "usually 1.1", not "1.0" and it needs an
@c xref to Assigning revisions
@item
Unless you use the @samp{-r rev} (@pxref{commit
options}) flag when @var{new} is committed its revision
numbers will start at 1.0 again.
@end ignore
@end itemize

@c ---------------------------------------------------------------------
@node Moving directories
@section Moving and renaming directories
@cindex Moving directories
@cindex Renaming directories
@cindex Directories, moving

The normal way to rename or move a directory is to
rename or move each file within it as described in
@ref{Outside}.  Then check out with the @samp{-P}
option, as described in @ref{Removing directories}.

If you really want to hack the repository to rename or
delete a directory in the repository, you can do it
like this:

@enumerate
@item
Inform everyone who has a checked out copy of the directory that the
directory will be renamed.  They should commit all their changes in all their
copies of the project containing the directory to be removed, and remove
all their working copies of said project, before you take the steps below.

@item
Rename the directory inside the repository.

@example
$ cd $CVSROOT/@var{parent-dir}
$ mv @var{old-dir} @var{new-dir}
@end example

@item
Fix the @sc{cvs} administrative files, if necessary (for
instance if you renamed an entire module).

@item
Tell everyone that they can check out again and continue
working.

@end enumerate

If someone had a working copy the @sc{cvs} commands will
cease to work for him, until he removes the directory
that disappeared inside the repository.

It is almost always better to move the files in the
directory instead of moving the directory.  If you move the
directory you are unlikely to be able to retrieve old
releases correctly, since they probably depend on the
name of the directories.

@c ---------------------------------------------------------------------
@node History browsing
@chapter History browsing
@cindex History browsing
@cindex Traceability
@cindex Isolation

@ignore
@c This is too long for an introduction (goal is
@c one 20x80 character screen), and also mixes up a
@c variety of issues (parallel development, history,
@c maybe even touches on process control).

@c -- @quote{To lose ones history is to lose ones soul.}
@c -- ///
@c -- ///Those who cannot remember the past are condemned to repeat it.
@c -- ///               -- George Santayana
@c -- ///

@sc{cvs} tries to make it easy for a group of people to work
together.  This is done in two ways:

@itemize @bullet
@item
Isolation---You have your own working copy of the
source.  You are not affected by modifications made by
others until you decide to incorporate those changes
(via the @code{update} command---@pxref{update}).

@item
Traceability---When something has changed, you can
always see @emph{exactly} what changed.
@end itemize

There are several features of @sc{cvs} that together lead
to traceability:

@itemize @bullet
@item
Each revision of a file has an accompanying log
message.

@item
All commits are optionally logged to a central history
database.

@item
Logging information can be sent to a user-defined
program (@pxref{loginfo}).
@end itemize

@c -- More text here.

This chapter should talk about the history file, the
@code{log} command, the usefulness of ChangeLogs
even when you run @sc{cvs}, and things like that.

@end ignore

@c kind of lame, in a lot of ways the above text inside
@c the @ignore motivates this chapter better
Once you have used @sc{cvs} to store a version control
history---what files have changed when, how, and by
whom, there are a variety of mechanisms for looking
through the history.

@c FIXME: should also be talking about how you look at
@c old revisions (e.g. "cvs update -p -r 1.2 foo.c").
@menu
* log messages::                Log messages
* history database::            The history database
* user-defined logging::        User-defined logging
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node log messages
@section Log messages

@c FIXME: @xref to place where we talk about how to
@c specify message to commit.
Whenever you commit a file you specify a log message.

@c FIXME: bring the information here, and get rid of or
@c greatly shrink the "log" node.
To look through the log messages which have been
specified for every revision which has been committed,
use the @code{cvs log} command (@pxref{log}).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node history database
@section The history database

@c FIXME: bring the information from the history file
@c and history nodes here.  Rewrite it to be motivated
@c better (start out by clearly explaining what gets
@c logged in history, for example).
You can use the history file (@pxref{history file}) to
log various @sc{cvs} actions.  To retrieve the
information from the history file, use the @code{cvs
history} command (@pxref{history}).

Note: you can control what is logged to this file by using the
@samp{LogHistory} keyword in the @file{CVSROOT/config} file
(@pxref{config}).

@c
@c The history database has many problems:
@c * It is very unclear what field means what.  This
@c could be improved greatly by better documentation,
@c but there are still non-orthogonalities (for
@c example, tag does not record the "repository"
@c field but most records do).
@c * Confusion about files, directories, and modules.
@c Some commands record one, some record others.
@c * File removal is not logged.  There is an 'R'
@c record type documented, but CVS never uses it.
@c * Tags are only logged for the "cvs rtag" command,
@c not "cvs tag".  The fix for this is not completely
@c clear (see above about modules vs. files).
@c * Are there other cases of operations that are not
@c logged?  One would hope for all changes to the
@c repository to be logged somehow (particularly
@c operations like tagging, "cvs admin -k", and other
@c operations which do not record a history that one
@c can get with "cvs log").  Operations on the working
@c directory, like export, get, and release, are a
@c second category also covered by the current "cvs
@c history".
@c * The history file does not record the options given
@c to a command.  The most serious manifestation of
@c this is perhaps that it doesn't record whether a command
@c was recursive.  It is not clear to me whether one
@c wants to log at a level very close to the command
@c line, as a sort of way of logging each command
@c (more or less), or whether one wants
@c to log more at the level of what was changed (or
@c something in between), but either way the current
@c information has pretty big gaps.
@c * Further details about a tag--like whether it is a
@c branch tag or, if a non-branch tag, which branch it
@c is on.  One can find out this information about the
@c tag as it exists _now_, but if the tag has been
@c moved, one doesn't know what it was like at the time
@c the history record was written.
@c * Whether operating on a particular tag, date, or
@c options was implicit (sticky) or explicit.
@c
@c Another item, only somewhat related to the above, is a
@c way to control what is logged in the history file.
@c This is probably the only good way to handle
@c different people having different ideas about
@c information/space tradeoffs.
@c
@c It isn't really clear that it makes sense to try to
@c patch up the history file format as it exists now to
@c include all that stuff.  It might be better to
@c design a whole new CVSROOT/nhistory file and "cvs
@c nhistory" command, or some such, or in some other
@c way trying to come up with a clean break from the
@c past, which can address the above concerns.  Another
@c open question is how/whether this relates to
@c taginfo/loginfo/etc.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node user-defined logging
@section User-defined logging

@c FIXME: probably should centralize this information
@c here, at least to some extent.  Maybe by moving the
@c loginfo, etc., nodes here and replacing
@c the "user-defined logging" node with one node for
@c each method.
You can customize @sc{cvs} to log various kinds of
actions, in whatever manner you choose.  These
mechanisms operate by executing a script at various
times.  The script might append a message to a file
listing the information and the programmer who created
it, or send mail to a group of developers, or, perhaps,
post a message to a particular newsgroup.  To log
commits, use the @file{loginfo} file (@pxref{loginfo}).
To log tags, use the @file{taginfo} file (@pxref{taginfo}).
@c FIXME: What is difference between doing it in the
@c modules file and using loginfo/taginfo?  Why should
@c user use one or the other?
To log checkouts, exports, and tags,
respectively, you can also use the
@samp{-o}, @samp{-e}, and @samp{-t} options in the
modules file.  For a more flexible way of giving
notifications to various users, which requires less in
the way of keeping centralized scripts up to date, use
the @code{cvs watch add} command (@pxref{Getting
Notified}); this command is useful even if you are not
using @code{cvs watch on}.

@c ---------------------------------------------------------------------
@node Binary files
@chapter Handling binary files
@cindex Binary files

The most common use for @sc{cvs} is to store text
files.  With text files, @sc{cvs} can merge revisions,
display the differences between revisions in a
human-visible fashion, and other such operations.
However, if you are willing to give up a few of these
abilities, @sc{cvs} can store binary files.  For
example, one might store a web site in @sc{cvs}
including both text files and binary images.

@menu
* Binary why::     More details on issues with binary files
* Binary howto::   How to store them
@end menu

@node Binary why
@section The issues with binary files

While the need to manage binary files may seem obvious
if the files that you customarily work with are binary,
putting them into version control does present some
additional issues.

One basic function of version control is to show the
differences between two revisions.  For example, if
someone else checked in a new version of a file, you
may wish to look at what they changed and determine
whether their changes are good.  For text files,
@sc{cvs} provides this functionality via the @code{cvs
diff} command.  For binary files, it may be possible to
extract the two revisions and then compare them with a
tool external to @sc{cvs} (for example, word processing
software often has such a feature).  If there is no
such tool, one must track changes via other mechanisms,
such as urging people to write good log messages, and
hoping that the changes they actually made were the
changes that they intended to make.

Another ability of a version control system is the
ability to merge two revisions.  For @sc{cvs} this
happens in two contexts.  The first is when users make
changes in separate working directories
(@pxref{Multiple developers}).  The second is when one
merges explicitly with the @samp{update -j} command
(@pxref{Branching and merging}).

In the case of text
files, @sc{cvs} can merge changes made independently,
and signal a conflict if the changes conflict.  With
binary files, the best that @sc{cvs} can do is present
the two different copies of the file, and leave it to
the user to resolve the conflict.  The user may choose
one copy or the other, or may run an external merge
tool which knows about that particular file format, if
one exists.
Note that having the user merge relies primarily on the
user to not accidentally omit some changes, and thus is
potentially error prone.

If this process is thought to be undesirable, the best
choice may be to avoid merging.  To avoid the merges
that result from separate working directories, see the
discussion of reserved checkouts (file locking) in
@ref{Multiple developers}.  To avoid the merges
resulting from branches, restrict use of branches.

@node Binary howto
@section How to store binary files

There are two issues with using @sc{cvs} to store
binary files.  The first is that @sc{cvs} by default
converts line endings between the canonical form in
which they are stored in the repository (linefeed
only), and the form appropriate to the operating system
in use on the client (for example, carriage return
followed by line feed for Windows NT).

The second is that a binary file might happen to
contain data which looks like a keyword (@pxref{Keyword
substitution}), so keyword expansion must be turned
off.

@c FIXME: the third is that one can't do merges with
@c binary files.  xref to Multiple Developers and the
@c reserved checkout issues.

The @samp{-kb} option available with some @sc{cvs}
commands insures that neither line ending conversion
nor keyword expansion will be done.

Here is an example of how you can create a new file
using the @samp{-kb} flag:

@example
$ echo '$@splitrcskeyword{Id}$' > kotest
$ cvs add -kb -m"A test file" kotest
$ cvs ci -m"First checkin; contains a keyword" kotest
@end example

If a file accidentally gets added without @samp{-kb},
one can use the @code{cvs admin} command to recover.
For example:

@example
$ echo '$@splitrcskeyword{Id}$' > kotest
$ cvs add -m"A test file" kotest
$ cvs ci -m"First checkin; contains a keyword" kotest
$ cvs admin -kb kotest
$ cvs update -A kotest
# @r{For non-unix systems:}
# @r{Copy in a good copy of the file from outside CVS}
$ cvs commit -m "make it binary" kotest
@end example

@c Trying to describe this for both unix and non-unix
@c in the same description is very confusing.  Might
@c want to split the two, or just ditch the unix "shortcut"
@c (unixheads don't do much with binary files, anyway).
@c This used to say "(Try the above example, and do a
@c @code{cat kotest} after every command)".  But that
@c only really makes sense for the unix case.
When you check in the file @file{kotest} the file is
not preserved as a binary file, because you did not
check it in as a binary file.  The @code{cvs
admin -kb} command sets the default keyword
substitution method for this file, but it does not
alter the working copy of the file that you have.  If you need to
cope with line endings (that is, you are using
@sc{cvs} on a non-unix system), then you need to
check in a new copy of the file, as shown by the
@code{cvs commit} command above.
On unix, the @code{cvs update -A} command suffices.
@c FIXME: should also describe what the *other users*
@c need to do, if they have checked out copies which
@c have been corrupted by lack of -kb.  I think maybe
@c "cvs update -kb" or "cvs
@c update -A" would suffice, although the user who
@c reported this suggested removing the file, manually
@c removing it from CVS/Entries, and then "cvs update"
(Note that you can use @code{cvs log} to determine the default keyword
substitution method for a file and @code{cvs status} to determine
the keyword substitution method for a working copy.)

However, in using @code{cvs admin -k} to change the
keyword expansion, be aware that the keyword expansion
mode is not version controlled.  This means that, for
example, that if you have a text file in old releases,
and a binary file with the same name in new releases,
@sc{cvs} provides no way to check out the file in text
or binary mode depending on what version you are
checking out.  There is no good workaround for this
problem.

You can also set a default for whether @code{cvs add}
and @code{cvs import} treat a file as binary based on
its name; for example you could say that files who
names end in @samp{.exe} are binary.  @xref{Wrappers}.
There is currently no way to have @sc{cvs} detect
whether a file is binary based on its contents.  The
main difficulty with designing such a feature is that
it is not clear how to distinguish between binary and
non-binary files, and the rules to apply would vary
considerably with the operating system.
@c For example, it would be good on MS-DOS-family OSes
@c for anything containing ^Z to be binary.  Having
@c characters with the 8th bit set imply binary is almost
@c surely a bad idea in the context of ISO-8859-* and
@c other such character sets.  On VMS or the Mac, we
@c could use the OS's file typing.  This is a
@c commonly-desired feature, and something of this sort
@c may make sense.  But there are a lot of pitfalls here.
@c
@c Another, probably better, way to tell is to read the
@c file in text mode, write it to a temp file in text
@c mode, and then do a binary mode compare of the two
@c files.  If they differ, it is a binary file.  This
@c might have problems on VMS (or some other system
@c with several different text modes), but in general
@c should be relatively portable.  The only other
@c downside I can think of is that it would be fairly
@c slow, but that is perhaps a small price to pay for
@c not having your files corrupted.  Another issue is
@c what happens if you import a text file with bare
@c linefeeds on Windows.  Such files will show up on
@c Windows sometimes (I think some native windows
@c programs even write them, on occasion).  Perhaps it
@c is reasonable to treat such files as binary; after
@c all it is something of a presumption to assume that
@c the user would want the linefeeds converted to CRLF.

@c ---------------------------------------------------------------------
@node Multiple developers
@chapter Multiple developers
@cindex Multiple developers
@cindex Team of developers
@cindex File locking
@cindex Locking files
@cindex Working copy
@cindex Reserved checkouts
@cindex Unreserved checkouts
@cindex RCS-style locking

When more than one person works on a software project
things often get complicated.  Often, two people try to
edit the same file simultaneously.  One solution, known
as @dfn{file locking} or @dfn{reserved checkouts}, is
to allow only one person to edit each file at a time.
This is the only solution with some version control
systems, including @sc{rcs} and @sc{sccs}.  Currently
the usual way to get reserved checkouts with @sc{cvs}
is the @code{cvs admin -l} command (@pxref{admin
options}).  This is not as nicely integrated into
@sc{cvs} as the watch features, described below, but it
seems that most people with a need for reserved
checkouts find it adequate.
@c Or "find it better than worrying about implementing
@c nicely integrated reserved checkouts" or ...?
It also may be possible to use the watches
features described below, together with suitable
procedures (not enforced by software), to avoid having
two people edit at the same time.

@c Our unreserved checkout model might not
@c be quite the same as others.  For example, I
@c think that some systems will tend to create a branch
@c in the case where CVS prints "up-to-date check failed".
@c It isn't clear to me whether we should try to
@c explore these subtleties; it could easily just
@c confuse people.
The default model with @sc{cvs} is known as
@dfn{unreserved checkouts}.  In this model, developers
can edit their own @dfn{working copy} of a file
simultaneously.  The first person that commits his
changes has no automatic way of knowing that another
has started to edit it.  Others will get an error
message when they try to commit the file.  They must
then use @sc{cvs} commands to bring their working copy
up to date with the repository revision.  This process
is almost automatic.

@c FIXME? should probably use the word "watch" here, to
@c tie this into the text below and above.
@sc{cvs} also supports mechanisms which facilitate
various kinds of communication, without actually
enforcing rules like reserved checkouts do.

The rest of this chapter describes how these various
models work, and some of the issues involved in
choosing between them.

@ignore
Here is a draft reserved checkout design or discussion
of the issues.  This seems like as good a place as any
for this.

Might want a cvs lock/cvs unlock--in which the names
differ from edit/unedit because the network must be up
for these to work.  unedit gives an error if there is a
reserved checkout in place (so that people don't
accidentally leave locks around); unlock gives an error
if one is not in place (this is more arguable; perhaps
it should act like unedit in that case).

On the other hand, might want it so that emacs,
scripts, etc., can get ready to edit a file without
having to know which model is in use.  In that case we
would have a "cvs watch lock" (or .cvsrc?) (that is,
three settings, "on", "off", and "lock").  Having cvs
watch lock set would cause a get to record in the CVS
directory which model is in use, and cause "cvs edit"
to change behaviors.  We'd want a way to query which
setting is in effect (this would be handy even if it is
only "on" or "off" as presently).  If lock is in
effect, then commit would require a lock before
allowing a checkin; chmod wouldn't suffice (might be
debatable--see chmod comment below, in watches--but it
is the way people expect RCS to work and I can't think
of any significant downside.  On the other hand, maybe
it isn't worth bothering, because people who are used
to RCS wouldn't think to use chmod anyway).

Implementation: use file attributes or use RCS
locking.  The former avoids more dependence on RCS
behaviors we will need to re-implement as we librarify
RCS, and makes it easier to import/export RCS files (in
that context, want to ignore the locker field).  But
note that RCS locks are per-branch, which is the
correct behavior (this is also an issue for the "watch
on" features; they should be per-branch too).

Here are a few more random notes about implementation
details, assuming "cvs watch lock" and

CVS/Watched file?  Or try to fit this into CVS/Entries somehow?
Cases: (1) file is checked out (unreserved or with watch on) by old
version of @sc{cvs}, now we do something with new one, (2) file is checked
out by new version, now we do something with old one.

Remote protocol would have a "Watched" analogous to "Mode".  Of course
it would apply to all Updated-like requests.  How do we keep this
setting up to date?  I guess that there wants to be a Watched request,
and the server would send a new one if it isn't up to date? (Ugh--hard
to implement and slows down "cvs -q update"--is there an easier way?)

"cvs edit"--checks CVS/Watched, and if watch lock, then sends
"edit-lock" request.  Which comes back with a Checked-in with
appropriate Watched (off, on, lock, locked, or some such?), or error
message if already locked.

"cvs commit"--only will commit if off/on/locked.  lock is not OK.

Doc:
note that "cvs edit" must be connected to network if watch lock is in
effect.

Talk about what to do if someone has locked a file and you want to
edit that file.  (breaking locks, or lack thereof).


One other idea (which could work along with the
existing "cvs admin -l" reserved checkouts, as well as
the above):

"cvs editors" could show who has the file locked, if
someone does.

@end ignore

@menu
* File status::                 A file can be in several states
* Updating a file::             Bringing a file up-to-date
* Conflicts example::           An informative example
* Informing others::            To cooperate you must inform
* Concurrency::                 Simultaneous repository access
* Watches::                     Mechanisms to track who is editing files
* Choosing a model::            Reserved or unreserved checkouts?
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node File status
@section File status
@cindex File status
@cindex Status of a file

@c Shouldn't this start with an example or something,
@c introducing the unreserved checkout model?  Before we
@c dive into listing states?
Based on what operations you have performed on a
checked out file, and what operations others have
performed to that file in the repository, one can
classify a file in a number of states.  The states, as
reported by the @code{status} command, are:

@c The order of items is chosen to group logically
@c similar outputs together.
@c People who want alphabetical can use the index...
@table @asis
@cindex Up-to-date
@item Up-to-date
The file is identical with the latest revision in the
repository for the branch in use.
@c FIXME: should we clarify "in use"?  The answer is
@c sticky tags, and trying to distinguish branch sticky
@c tags from non-branch sticky tags seems rather awkward
@c here.
@c FIXME: What happens with non-branch sticky tags?  Is
@c a stuck file "Up-to-date" or "Needs checkout" or what?

@item Locally Modified
@cindex Locally Modified
You have edited the file, and not yet committed your changes.

@item Locally Added
@cindex Locally Added
You have added the file with @code{add}, and not yet
committed your changes.
@c There are many cases involving the file being
@c added/removed/modified in the working directory, and
@c added/removed/modified in the repository, which we
@c don't try to describe here.  I'm not sure that "cvs
@c status" produces a non-confusing output in most of
@c those cases.

@item Locally Removed
@cindex Locally Removed
You have removed the file with @code{remove}, and not yet
committed your changes.

@item Needs Checkout
@cindex Needs Checkout
Someone else has committed a newer revision to the
repository.  The name is slightly misleading; you will
ordinarily use @code{update} rather than
@code{checkout} to get that newer revision.

@item Needs Patch
@cindex Needs Patch
@c See also newb-123j0 in sanity.sh (although that case
@c should probably be changed rather than documented).
Like Needs Checkout, but the @sc{cvs} server will send
a patch rather than the entire file.  Sending a patch or
sending an entire file accomplishes the same thing.

@item Needs Merge
@cindex Needs Merge
Someone else has committed a newer revision to the repository, and you
have also made modifications to the file.

@item Unresolved Conflict
@cindex Unresolved Conflict
@c FIXCVS - This file status needs to be changed to some more informative
@c text that distinguishes it more clearly from each of the Locally Added,
@c File had conflicts on merge, and Unknown status types, but an exact and
@c succinct wording escapes me at the moment.
A file with the same name as this new file has been added to the repository
from a second workspace.  This file will need to be moved out of the way
to allow an @code{update} to complete.

@item File had conflicts on merge
@cindex File had conflicts on merge
@c is it worth saying that this message was "Unresolved
@c Conflict" in CVS 1.9 and earlier?  I'm inclined to
@c think that is unnecessarily confusing to new users.
This is like Locally Modified, except that a previous
@code{update} command gave a conflict.  If you have not
already done so, you need to
resolve the conflict as described in @ref{Conflicts example}.

@item Unknown
@cindex Unknown
@sc{cvs} doesn't know anything about this file.  For
example, you have created a new file and have not run
@code{add}.
@c
@c "Entry Invalid" and "Classify Error" are also in the
@c status.c.  The latter definitely indicates a CVS bug
@c (should it be worded more like "internal error" so
@c people submit bug reports if they see it?).  The former
@c I'm not as sure; I haven't tracked down whether/when it
@c appears in "cvs status" output.

@end table

To help clarify the file status, @code{status} also
reports the @code{Working revision} which is the
revision that the file in the working directory derives
from, and the @code{Repository revision} which is the
latest revision in the repository for the branch in
use.
@c FIXME: should we clarify "in use"?  The answer is
@c sticky tags, and trying to distinguish branch sticky
@c tags from non-branch sticky tags seems rather awkward
@c here.
@c FIXME: What happens with non-branch sticky tags?
@c What is the Repository Revision there?  See the
@c comment at vn_rcs in cvs.h, which is kind of
@c confused--we really need to document better what this
@c field contains.
@c Q: Should we document "New file!" and other such
@c outputs or are they self-explanatory?
@c FIXME: what about the date to the right of "Working
@c revision"?  It doesn't appear with client/server and
@c seems unnecessary (redundant with "ls -l") so
@c perhaps it should be removed for non-client/server too?
@c FIXME: Need some examples.
@c FIXME: Working revision can also be something like
@c "-1.3" for a locally removed file.  Not at all
@c self-explanatory (and it is possible that CVS should
@c be changed rather than documenting this).

@c Would be nice to have an @example showing output
@c from cvs status, with comments showing the xref
@c where each part of the output is described.  This
@c might fit in nicely if it is desirable to split this
@c node in two; one to introduce "cvs status" and one
@c to list each of the states.
The options to @code{status} are listed in
@ref{Invoking CVS}.  For information on its @code{Sticky tag}
and @code{Sticky date} output, see @ref{Sticky tags}.
For information on its @code{Sticky options} output,
see the @samp{-k} option in @ref{update options}.

You can think of the @code{status} and @code{update}
commands as somewhat complementary.  You use
@code{update} to bring your files up to date, and you
can use @code{status} to give you some idea of what an
@code{update} would do (of course, the state of the
repository might change before you actually run
@code{update}).  In fact, if you want a command to
display file status in a more brief format than is
displayed by the @code{status} command, you can invoke

@cindex update, to display file status
@example
$ cvs -n -q update
@end example

The @samp{-n} option means to not actually do the
update, but merely to display statuses; the @samp{-q}
option avoids printing the name of each directory.  For
more information on the @code{update} command, and
these options, see @ref{Invoking CVS}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Updating a file
@section Bringing a file up to date
@cindex Bringing a file up to date
@cindex Updating a file
@cindex Merging a file
@cindex Update, introduction

When you want to update or merge a file, use the @code{cvs update -d}
command.  For files that are not up to date this is roughly equivalent
to a @code{checkout} command: the newest revision of the file is
extracted from the repository and put in your working directory.  The
@code{-d} option, not necessary with @code{checkout}, tells @sc{cvs}
that you wish it to create directories added by other developers.

Your modifications to a file are never lost when you
use @code{update}.  If no newer revision exists,
running @code{update} has no effect.  If you have
edited the file, and a newer revision is available,
@sc{cvs} will merge all changes into your working copy.

For instance, imagine that you checked out revision 1.4 and started
editing it.  In the meantime someone else committed revision 1.5, and
shortly after that revision 1.6.  If you run @code{update} on the file
now, @sc{cvs} will incorporate all changes between revision 1.4 and 1.6 into
your file.

@cindex Overlap
If any of the changes between 1.4 and 1.6 were made too
close to any of the changes you have made, an
@dfn{overlap} occurs.  In such cases a warning is
printed, and the resulting file includes both
versions of the lines that overlap, delimited by
special markers.
@xref{update}, for a complete description of the
@code{update} command.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Conflicts example
@section Conflicts example
@cindex Merge, an example
@cindex Example of merge
@cindex driver.c (merge example)

Suppose revision 1.4 of @file{driver.c} contains this:

@example
#include <stdio.h>

void main()
@{
    parse();
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(nerr == 0 ? 0 : 1);
@}
@end example

@noindent
Revision 1.6 of @file{driver.c} contains this:

@example
#include <stdio.h>

int main(int argc,
         char **argv)
@{
    parse();
    if (argc != 1)
    @{
        fprintf(stderr, "tc: No args expected.\n");
        exit(1);
    @}
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(!!nerr);
@}
@end example

@noindent
Your working copy of @file{driver.c}, based on revision
1.4, contains this before you run @samp{cvs update}:
@c -- Really include "cvs"?

@example
#include <stdlib.h>
#include <stdio.h>

void main()
@{
    init_scanner();
    parse();
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(nerr == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
@}
@end example

@noindent
You run @samp{cvs update}:
@c -- Really include "cvs"?

@example
$ cvs update driver.c
RCS file: /usr/local/cvsroot/yoyodyne/tc/driver.c,v
retrieving revision 1.4
retrieving revision 1.6
Merging differences between 1.4 and 1.6 into driver.c
rcsmerge warning: overlaps during merge
cvs update: conflicts found in driver.c
C driver.c
@end example

@noindent
@cindex Conflicts (merge example)
@sc{cvs} tells you that there were some conflicts.
Your original working file is saved unmodified in
@file{.#driver.c.1.4}.  The new version of
@file{driver.c} contains this:

@example
#include <stdlib.h>
#include <stdio.h>

int main(int argc,
         char **argv)
@{
    init_scanner();
    parse();
    if (argc != 1)
    @{
        fprintf(stderr, "tc: No args expected.\n");
        exit(1);
    @}
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
@asis{}<<<<<<< driver.c
    exit(nerr == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
@asis{}=======
    exit(!!nerr);
@asis{}>>>>>>> 1.6
@}
@end example

@noindent
@cindex Markers, conflict
@cindex Conflict markers
@cindex <<<<<<<
@cindex >>>>>>>
@cindex =======

Note how all non-overlapping modifications are incorporated in your working
copy, and that the overlapping section is clearly marked with
@samp{<<<<<<<}, @samp{=======} and @samp{>>>>>>>}.

@cindex Resolving a conflict
@cindex Conflict resolution
You resolve the conflict by editing the file, removing the markers and
the erroneous line.  Suppose you end up with this file:
@c -- Add xref to the pcl-cvs manual when it talks
@c -- about this.
@example
#include <stdlib.h>
#include <stdio.h>

int main(int argc,
         char **argv)
@{
    init_scanner();
    parse();
    if (argc != 1)
    @{
        fprintf(stderr, "tc: No args expected.\n");
        exit(1);
    @}
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(nerr == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
@}
@end example

@noindent
You can now go ahead and commit this as revision 1.7.

@example
$ cvs commit -m "Initialize scanner. Use symbolic exit values." driver.c
Checking in driver.c;
/usr/local/cvsroot/yoyodyne/tc/driver.c,v  <--  driver.c
new revision: 1.7; previous revision: 1.6
done
@end example

For your protection, @sc{cvs} will refuse to check in a
file if a conflict occurred and you have not resolved
the conflict.  Currently to resolve a conflict, you
must change the timestamp on the file.  In previous
versions of @sc{cvs}, you also needed to
insure that the file contains no conflict markers.
Because
your file may legitimately contain conflict markers (that
is, occurrences of @samp{>>>>>>> } at the start of a
line that don't mark a conflict), the current
version of @sc{cvs} will print a warning and proceed to
check in the file.
@c The old behavior was really icky; the only way out
@c was to start hacking on
@c the @code{CVS/Entries} file or other such workarounds.
@c
@c If the timestamp thing isn't considered nice enough,
@c maybe there should be a "cvs resolved" command
@c which clears the conflict indication.  For a nice user
@c interface, this should be invoked by an interactive
@c merge tool like emerge rather than by the user
@c directly--such a tool can verify that the user has
@c really dealt with each conflict.

@cindex emerge
If you use release 1.04 or later of pcl-cvs (a @sc{gnu}
Emacs front-end for @sc{cvs}) you can use an Emacs
package called emerge to help you resolve conflicts.
See the documentation for pcl-cvs.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Informing others
@section Informing others about commits
@cindex Informing others
@cindex Spreading information
@cindex Mail, automatic mail on commit

It is often useful to inform others when you commit a
new revision of a file.  The @file{loginfo} file can be
used to automate this process.
@xref{loginfo}.  You can use these features of @sc{cvs}
to, for instance, instruct @sc{cvs} to mail a
message to all developers, or post a message to a local
newsgroup.
@c -- More text would be nice here.

@node Concurrency
@section Several developers simultaneously attempting to run CVS

@cindex Locks, cvs, introduction
@c For a discussion of *why* CVS creates locks, see
@c the comment at the start of src/lock.c
If several developers try to run @sc{cvs} at the same
time, one may get the following message:

@example
[11:43:23] waiting for bach's lock in /usr/local/cvsroot/foo
@end example

@cindex #cvs.rfl, removing
@cindex #cvs.wfl, removing
@cindex #cvs.lock, removing
@sc{cvs} will try again every 30 seconds, and either
continue with the operation or print the message again,
if it still needs to wait.  If a lock seems to stick
around for an undue amount of time, find the person
holding the lock and ask them about the cvs command
they are running.  If they aren't running a cvs
command, look in the repository directory mentioned in
the message and remove files which they own whose names
start with @file{#cvs.rfl},
@file{#cvs.wfl}, or @file{#cvs.lock}.

Note that these locks are to protect @sc{cvs}'s
internal data structures and have no relationship to
the word @dfn{lock} in the sense used by
@sc{rcs}---which refers to reserved checkouts
(@pxref{Multiple developers}).

Any number of people can be reading from a given
repository at a time; only when someone is writing do
the locks prevent other people from reading or writing.

@cindex Atomic transactions, lack of
@cindex Transactions, atomic, lack of
@c the following talks about what one might call commit/update
@c atomicity.
@c Probably also should say something about
@c commit/commit atomicity, that is, "An update will
@c not get partial versions of more than one commit".
@c CVS currently has this property and I guess we can
@c make it a documented feature.
@c For example one person commits
@c a/one.c and b/four.c and another commits a/two.c and
@c b/three.c.  Then an update cannot get the new a/one.c
@c and a/two.c and the old b/four.c and b/three.c.
One might hope for the following property:

@quotation
If someone commits some changes in one cvs command,
then an update by someone else will either get all the
changes, or none of them.
@end quotation

@noindent
but @sc{cvs} does @emph{not} have this property.  For
example, given the files

@example
a/one.c
a/two.c
b/three.c
b/four.c
@end example

@noindent
if someone runs

@example
cvs ci a/two.c b/three.c
@end example

@noindent
and someone else runs @code{cvs update} at the same
time, the person running @code{update} might get only
the change to @file{b/three.c} and not the change to
@file{a/two.c}.

@node Watches
@section Mechanisms to track who is editing files
@cindex Watches

For many groups, use of @sc{cvs} in its default mode is
perfectly satisfactory.  Users may sometimes go to
check in a modification only to find that another
modification has intervened, but they deal with it and
proceed with their check in.  Other groups prefer to be
able to know who is editing what files, so that if two
people try to edit the same file they can choose to
talk about who is doing what when rather than be
surprised at check in time.  The features in this
section allow such coordination, while retaining the
ability of two developers to edit the same file at the
same time.

@c Some people might ask why CVS does not enforce the
@c rule on chmod, by requiring a cvs edit before a cvs
@c commit.  The main reason is that it could always be
@c circumvented--one could edit the file, and
@c then when ready to check it in, do the cvs edit and put
@c in the new contents and do the cvs commit.  One
@c implementation note: if we _do_ want to have cvs commit
@c require a cvs edit, we should store the state on
@c whether the cvs edit has occurred in the working
@c directory, rather than having the server try to keep
@c track of what working directories exist.
@c FIXME: should the above discussion be part of the
@c manual proper, somewhere, not just in a comment?
For maximum benefit developers should use @code{cvs
edit} (not @code{chmod}) to make files read-write to
edit them, and @code{cvs release} (not @code{rm}) to
discard a working directory which is no longer in use,
but @sc{cvs} is not able to enforce this behavior.

@c I'm a little dissatisfied with this presentation,
@c because "watch on"/"edit"/"editors" are one set of
@c functionality, and "watch add"/"watchers" is another
@c which is somewhat orthogonal even though they interact in
@c various ways.  But I think it might be
@c confusing to describe them separately (e.g. "watch
@c add" with loginfo).  I don't know.

@menu
* Setting a watch::             Telling CVS to watch certain files
* Getting Notified::            Telling CVS to notify you
* Editing files::               How to edit a file which is being watched
* Watch information::           Information about who is watching and editing
* Watches Compatibility::       Watches interact poorly with CVS 1.6 or earlier
@end menu

@node Setting a watch
@subsection Telling CVS to watch certain files

To enable the watch features, you first specify that
certain files are to be watched.

@cindex watch on (subcommand)
@deffn Command {cvs watch on} [@code{-lR}] [@var{files}]@dots{}

@cindex Read-only files, and watches
Specify that developers should run @code{cvs edit}
before editing @var{files}.  @sc{cvs} will create working
copies of @var{files} read-only, to remind developers
to run the @code{cvs edit} command before working on
them.

If @var{files} includes the name of a directory, @sc{cvs}
arranges to watch all files added to the corresponding
repository directory, and sets a default for files
added in the future; this allows the user to set
notification policies on a per-directory basis.  The
contents of the directory are processed recursively,
unless the @code{-l} option is given.
The @code{-R} option can be used to force recursion if the @code{-l}
option is set in @file{~/.cvsrc} (@pxref{~/.cvsrc}).

If @var{files} is omitted, it defaults to the current directory.

@cindex watch off (subcommand)
@end deffn

@deffn Command {cvs watch off} [@code{-lR}] [@var{files}]@dots{}

Do not create @var{files} read-only on checkout; thus,
developers will not be reminded to use @code{cvs edit}
and @code{cvs unedit}.
@ignore
@sc{cvs} will check out @var{files}
read-write as usual, unless other permissions override
due to the @code{PreservePermissions} option being
enabled in the @file{config} administrative file
(@pxref{Special Files}, @pxref{config})
@end ignore

The @var{files} and options are processed as for @code{cvs
watch on}.

@end deffn

@node Getting Notified
@subsection Telling CVS to notify you

You can tell @sc{cvs} that you want to receive
notifications about various actions taken on a file.
You can do this without using @code{cvs watch on} for
the file, but generally you will want to use @code{cvs
watch on}, to remind developers to use the @code{cvs edit}
command.

@cindex watch add (subcommand)
@deffn Command {cvs watch add} [@code{-lR}] [@code{-a} @var{action}]@dots{} [@var{files}]@dots{}

Add the current user to the list of people to receive notification of
work done on @var{files}.

The @code{-a} option specifies what kinds of events @sc{cvs} should notify
the user about.  @var{action} is one of the following:

@table @code

@item edit
Another user has applied the @code{cvs edit} command (described
below) to a watched file.

@item commit
Another user has committed changes to one of the named @var{files}.

@item unedit
Another user has abandoned editing a file (other than by committing changes).
They can do this in several ways, by:

@itemize @bullet

@item
applying the @code{cvs unedit} command (described below) to the file

@item
applying the @code{cvs release} command (@pxref{release}) to the file's parent directory
(or recursively to a directory more than one level up)

@item
deleting the file and allowing @code{cvs update} to recreate it

@end itemize

@item all
All of the above.

@item none
None of the above.  (This is useful with @code{cvs edit},
described below.)

@end table

The @code{-a} option may appear more than once, or not at all.  If
omitted, the action defaults to @code{all}.

The @var{files} and options are processed as for
@code{cvs watch on}.

@end deffn


@cindex watch remove (subcommand)
@deffn Command {cvs watch remove} [@code{-lR}] [@code{-a} @var{action}]@dots{} [@var{files}]@dots{}

Remove a notification request established using @code{cvs watch add};
the arguments are the same.  If the @code{-a} option is present, only
watches for the specified actions are removed.

@end deffn

@cindex notify (admin file)
When the conditions exist for notification, @sc{cvs}
calls the @file{notify} administrative file.  Edit
@file{notify} as one edits the other administrative
files (@pxref{Intro administrative files}).  This
file follows the usual conventions for administrative
files (@pxref{syntax}), where each line is a regular
expression followed by a command to execute.  The
command should contain a single occurrence of @samp{%s}
which will be replaced by the user to notify; the rest
of the information regarding the notification will be
supplied to the command on standard input.  The
standard thing to put in the @code{notify} file is the
single line:

@example
ALL mail %s -s "CVS notification"
@end example

@noindent
This causes users to be notified by electronic mail.
@c FIXME: should it be this hard to set up this
@c behavior (and the result when one fails to do so,
@c silent failure to notify, so non-obvious)?  Should
@c CVS give a warning if no line in notify matches (and
@c document the use of "DEFAULT :" for the case where
@c skipping the notification is indeed desired)?

@cindex users (admin file)
Note that if you set this up in the straightforward
way, users receive notifications on the server machine.
One could of course write a @file{notify} script which
directed notifications elsewhere, but to make this
easy, @sc{cvs} allows you to associate a notification
address for each user.  To do so create a file
@file{users} in @file{CVSROOT} with a line for each
user in the format @var{user}:@var{value}.  Then
instead of passing the name of the user to be notified
to @file{notify}, @sc{cvs} will pass the @var{value}
(normally an email address on some other machine).

@sc{cvs} does not notify you for your own changes.
Currently this check is done based on whether the user
name of the person taking the action which triggers
notification matches the user name of the person
getting notification.  In fact, in general, the watches
features only track one edit by each user.  It probably
would be more useful if watches tracked each working
directory separately, so this behavior might be worth
changing.
@c "behavior might be worth changing" is an effort to
@c point to future directions while also not promising
@c that "they" (as in "why don't they fix CVS to....")
@c will do this.
@c one implementation issue is identifying whether a
@c working directory is same or different.  Comparing
@c pathnames/hostnames is hopeless, but having the server
@c supply a serial number which the client stores in the
@c CVS directory as a magic cookie should work.

@node Editing files
@subsection How to edit a file which is being watched

@cindex Checkout, as term for getting ready to edit
Since a file which is being watched is checked out
read-only, you cannot simply edit it.  To make it
read-write, and inform others that you are planning to
edit it, use the @code{cvs edit} command.  Some systems
call this a @dfn{checkout}, but @sc{cvs} uses that term
for obtaining a copy of the sources (@pxref{Getting the
source}), an operation which those systems call a
@dfn{get} or a @dfn{fetch}.
@c Issue to think about: should we transition CVS
@c towards the "get" terminology?  "cvs get" is already a
@c synonym for "cvs checkout" and that section of the
@c manual refers to "Getting the source".  If this is
@c done, needs to be done gingerly (for example, we should
@c still accept "checkout" in .cvsrc files indefinitely
@c even if the CVS's messages are changed from "cvs checkout: "
@c to "cvs get: ").
@c There is a concern about whether "get" is not as
@c good for novices because it is a more general term
@c than "checkout" (and thus arguably harder to assign
@c a technical meaning for).

@cindex edit (subcommand)
@deffn Command {cvs edit} [@code{-lR}] [@code{-a} @var{action}]@dots{} [@var{files}]@dots{}

Prepare to edit the working files @var{files}.  @sc{cvs} makes the
@var{files} read-write, and notifies users who have requested
@code{edit} notification for any of @var{files}.

The @code{cvs edit} command accepts the same options as the
@code{cvs watch add} command, and establishes a temporary watch for the
user on @var{files}; @sc{cvs} will remove the watch when @var{files} are
@code{unedit}ed or @code{commit}ted.  If the user does not wish to
receive notifications, she should specify @code{-a none}.

The @var{files} and the options are processed as for the @code{cvs
watch} commands.

@ignore
@strong{Caution: If the @code{PreservePermissions}
option is enabled in the repository (@pxref{config}),
@sc{cvs} will not change the permissions on any of the
@var{files}.  The reason for this change is to ensure
that using @samp{cvs edit} does not interfere with the
ability to store file permissions in the @sc{cvs}
repository.}
@end ignore

@end deffn

Normally when you are done with a set of changes, you
use the @code{cvs commit} command, which checks in your
changes and returns the watched files to their usual
read-only state.  But if you instead decide to abandon
your changes, or not to make any changes, you can use
the @code{cvs unedit} command.

@cindex unedit (subcommand)
@cindex Abandoning work
@cindex Reverting to repository version
@deffn Command {cvs unedit} [@code{-lR}] [@var{files}]@dots{}

Abandon work on the working files @var{files}, and revert them to the
repository versions on which they are based.  @sc{cvs} makes those
@var{files} read-only for which users have requested notification using
@code{cvs watch on}.  @sc{cvs} notifies users who have requested @code{unedit}
notification for any of @var{files}.

The @var{files} and options are processed as for the
@code{cvs watch} commands.

If watches are not in use, the @code{unedit} command
probably does not work, and the way to revert to the
repository version is with the command @code{cvs update -C file}
(@pxref{update}).
The meaning is
not precisely the same; the latter may also
bring in some changes which have been made in the
repository since the last time you updated.
@c It would be a useful enhancement to CVS to make
@c unedit work in the non-watch case as well.
@end deffn

When using client/server @sc{cvs}, you can use the
@code{cvs edit} and @code{cvs unedit} commands even if
@sc{cvs} is unable to successfully communicate with the
server; the notifications will be sent upon the next
successful @sc{cvs} command.

@node Watch information
@subsection Information about who is watching and editing

@cindex watchers (subcommand)
@deffn Command {cvs watchers} [@code{-lR}] [@var{files}]@dots{}

List the users currently watching changes to @var{files}.  The report
includes the files being watched, and the mail address of each watcher.

The @var{files} and options are processed as for the
@code{cvs watch} commands.

@end deffn


@cindex editors (subcommand)
@deffn Command {cvs editors} [@code{-lR}] [@var{files}]@dots{}

List the users currently working on @var{files}.  The report
includes the mail address of each user, the time when the user began
working with the file, and the host and path of the working directory
containing the file.

The @var{files} and options are processed as for the
@code{cvs watch} commands.

@end deffn

@node Watches Compatibility
@subsection Using watches with old versions of CVS

@cindex CVS 1.6, and watches
If you use the watch features on a repository, it
creates @file{CVS} directories in the repository and
stores the information about watches in that directory.
If you attempt to use @sc{cvs} 1.6 or earlier with the
repository, you get an error message such as the
following (all on one line):

@example
cvs update: cannot open CVS/Entries for reading:
No such file or directory
@end example

@noindent
and your operation will likely be aborted.  To use the
watch features, you must upgrade all copies of @sc{cvs}
which use that repository in local or server mode.  If
you cannot upgrade, use the @code{watch off} and
@code{watch remove} commands to remove all watches, and
that will restore the repository to a state which
@sc{cvs} 1.6 can cope with.

@node Choosing a model
@section Choosing between reserved or unreserved checkouts
@cindex Choosing, reserved or unreserved checkouts

Reserved and unreserved checkouts each have pros and
cons.  Let it be said that a lot of this is a matter of
opinion or what works given different groups' working
styles, but here is a brief description of some of the
issues.  There are many ways to organize a team of
developers.  @sc{cvs} does not try to enforce a certain
organization.  It is a tool that can be used in several
ways.

Reserved checkouts can be very counter-productive.  If
two persons want to edit different parts of a file,
there may be no reason to prevent either of them from
doing so.  Also, it is common for someone to take out a
lock on a file, because they are planning to edit it,
but then forget to release the lock.

@c "many groups"?  specifics?  cites to papers on this?
@c some way to weasel-word it a bit more so we don't
@c need facts :-)?
People, especially people who are familiar with
reserved checkouts, often wonder how often conflicts
occur if unreserved checkouts are used, and how
difficult they are to resolve.  The experience with
many groups is that they occur rarely and usually are
relatively straightforward to resolve.

The rarity of serious conflicts may be surprising, until one realizes
that they occur only when two developers disagree on the proper design
for a given section of code; such a disagreement suggests that the
team has not been communicating properly in the first place.  In order
to collaborate under @emph{any} source management regimen, developers
must agree on the general design of the system; given this agreement,
overlapping changes are usually straightforward to merge.

In some cases unreserved checkouts are clearly
inappropriate.  If no merge tool exists for the kind of
file you are managing (for example word processor files
or files edited by Computer Aided Design programs), and
it is not desirable to change to a program which uses a
mergeable data format, then resolving conflicts is
going to be unpleasant enough that you generally will
be better off to simply avoid the conflicts instead, by
using reserved checkouts.

The watches features described above in @ref{Watches}
can be considered to be an intermediate model between
reserved checkouts and unreserved checkouts.  When you
go to edit a file, it is possible to find out who else
is editing it.  And rather than having the system
simply forbid both people editing the file, it can tell
you what the situation is and let you figure out
whether it is a problem in that particular case or not.
Therefore, for some groups it can be considered the
best of both the reserved checkout and unreserved
checkout worlds.

@c ---------------------------------------------------------------------
@node Revision management
@chapter Revision management
@cindex Revision management

@c -- This chapter could be expanded a lot.
@c -- Experiences are very welcome!

If you have read this far, you probably have a pretty
good grasp on what @sc{cvs} can do for you.  This
chapter talks a little about things that you still have
to decide.

If you are doing development on your own using @sc{cvs}
you could probably skip this chapter.  The questions
this chapter takes up become more important when more
than one person is working in a repository.

@menu
* When to commit::              Some discussion on the subject
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node When to commit
@section When to commit?
@cindex When to commit
@cindex Committing, when to
@cindex Policy

Your group should decide which policy to use regarding
commits.  Several policies are possible, and as your
experience with @sc{cvs} grows you will probably find
out what works for you.

If you commit files too quickly you might commit files
that do not even compile.  If your partner updates his
working sources to include your buggy file, he will be
unable to compile the code.  On the other hand, other
persons will not be able to benefit from the
improvements you make to the code if you commit very
seldom, and conflicts will probably be more common.

It is common to only commit files after making sure
that they can be compiled.  Some sites require that the
files pass a test suite.  Policies like this can be
enforced using the commitinfo file
(@pxref{commitinfo}), but you should think twice before
you enforce such a convention.  By making the
development environment too controlled it might become
too regimented and thus counter-productive to the real
goal, which is to get software written.

@c ---------------------------------------------------------------------
@node Keyword substitution
@chapter Keyword substitution
@cindex Keyword substitution
@cindex Keyword expansion
@cindex Identifying files

@comment   Be careful when editing this chapter.
@comment   Remember that this file is kept under
@comment   version control, so we must not accidentally
@comment   include a valid keyword in the running text.

As long as you edit source files inside a working
directory you can always find out the state of
your files via @samp{cvs status} and @samp{cvs log}.
But as soon as you export the files from your
development environment it becomes harder to identify
which revisions they are.

@sc{cvs} can use a mechanism known as @dfn{keyword
substitution} (or @dfn{keyword expansion}) to help
identifying the files.  Embedded strings of the form
@code{$@var{keyword}$} and
@code{$@var{keyword}:@dots{}$} in a file are replaced
with strings of the form
@code{$@var{keyword}:@var{value}$} whenever you obtain
a new revision of the file.

@menu
* Keyword list::                Keywords
* Using keywords::              Using keywords
* Avoiding substitution::       Avoiding substitution
* Substitution modes::          Substitution modes
* Log keyword::                 Problems with the $@splitrcskeyword{Log}$ keyword.
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Keyword list
@section Keyword List
@cindex Keyword List

@c FIXME: need some kind of example here I think,
@c perhaps in a
@c "Keyword intro" node.  The intro in the "Keyword
@c substitution" node itself seems OK, but to launch
@c into a list of the keywords somehow seems too abrupt.

This is a list of the keywords:

@table @code
@cindex Author keyword
@item $@splitrcskeyword{Author}$
The login name of the user who checked in the revision.

@cindex Date keyword
@item $@splitrcskeyword{Date}$
The date and time (UTC) the revision was checked in.

@cindex Header keyword
@item $@splitrcskeyword{Header}$
A standard header containing the full pathname of the
@sc{rcs} file, the revision number, the date (UTC), the
author, the state, and the locker (if locked).  Files
will normally never be locked when you use @sc{cvs}.

@cindex Id keyword
@item $@splitrcskeyword{Id}$
Same as @code{$@splitrcskeyword{Header}$}, except that the @sc{rcs}
filename is without a path.

@cindex Name keyword
@item $@splitrcskeyword{Name}$
Tag name used to check out this file.  The keyword is
expanded only if one checks out with an explicit tag
name.  For example, when running the command @code{cvs
co -r first}, the keyword expands to @samp{Name: first}.

@cindex Locker keyword
@item $@splitrcskeyword{Locker}$
The login name of the user who locked the revision
(empty if not locked, which is the normal case unless
@code{cvs admin -l} is in use).

@cindex Log keyword
@item $@splitrcskeyword{Log}$
The log message supplied during commit, preceded by a
header containing the @sc{rcs} filename, the revision
number, the author, and the date (UTC).  Existing log
messages are @emph{not} replaced.  Instead, the new log
message is inserted after @code{$@splitrcskeyword{Log}:@dots{}$}.
Each new line is prefixed with the same string which
precedes the @code{$Log} keyword.  For example, if the
file contains:

@example
  /* Here is what people have been up to:
   *
   * $@splitrcskeyword{Log}: frob.c,v $
   * Revision 1.1  1997/01/03 14:23:51  joe
   * Add the superfrobnicate option
   *
   */
@end example

@noindent
then additional lines which are added when expanding
the @code{$Log} keyword will be preceded by @samp{   * }.
Unlike previous versions of @sc{cvs} and @sc{rcs}, the
@dfn{comment leader} from the @sc{rcs} file is not used.
The @code{$Log} keyword is useful for
accumulating a complete change log in a source file,
but for several reasons it can be problematic.
@xref{Log keyword}.

@cindex RCSfile keyword
@item $@splitrcskeyword{RCSfile}$
The name of the RCS file without a path.

@cindex Revision keyword
@item $@splitrcskeyword{Revision}$
The revision number assigned to the revision.

@cindex Source keyword
@item $@splitrcskeyword{Source}$
The full pathname of the RCS file.

@cindex State keyword
@item $@splitrcskeyword{State}$
The state assigned to the revision.  States can be
assigned with @code{cvs admin -s}---see @ref{admin options}.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Using keywords
@section Using keywords

To include a keyword string you simply include the
relevant text string, such as @code{$@splitrcskeyword{Id}$}, inside the
file, and commit the file.  @sc{cvs} will automatically (Or,
more accurately, as part of the update run that
automatically happens after a commit.)
expand the string as part of the commit operation.

It is common to embed the @code{$@splitrcskeyword{Id}$} string in
the source files so that it gets passed through to
generated files.  For example, if you are managing
computer program source code, you might include a
variable which is initialized to contain that string.
Or some C compilers may provide a @code{#pragma ident}
directive.  Or a document management system might
provide a way to pass a string through to generated
files.

@c Would be nice to give an example, but doing this in
@c portable C is not possible and the problem with
@c picking any one language (VMS HELP files, Ada,
@c troff, whatever) is that people use CVS for all
@c kinds of files.

@cindex Ident (shell command)
The @code{ident} command (which is part of the @sc{rcs}
package) can be used to extract keywords and their
values from a file.  This can be handy for text files,
but it is even more useful for extracting keywords from
binary files.

@example
$ ident samp.c
samp.c:
     $@splitrcskeyword{Id}: samp.c,v 1.5 1993/10/19 14:57:32 ceder Exp $
$ gcc samp.c
$ ident a.out
a.out:
     $@splitrcskeyword{Id}: samp.c,v 1.5 1993/10/19 14:57:32 ceder Exp $
@end example

@cindex What (shell command)
S@sc{ccs} is another popular revision control system.
It has a command, @code{what}, which is very similar to
@code{ident} and used for the same purpose.  Many sites
without @sc{rcs} have @sc{sccs}.  Since @code{what}
looks for the character sequence @code{@@(#)} it is
easy to include keywords that are detected by either
command.  Simply prefix the keyword with the
magic @sc{sccs} phrase, like this:

@example
static char *id="@@(#) $@splitrcskeyword{Id}: ab.c,v 1.5 1993/10/19 14:57:32 ceder Exp $";
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Avoiding substitution
@section Avoiding substitution

Keyword substitution has its disadvantages.  Sometimes
you might want the literal text string
@samp{$@splitrcskeyword{Author}$} to appear inside a file without
@sc{cvs} interpreting it as a keyword and expanding it
into something like @samp{$@splitrcskeyword{Author}: ceder $}.

There is unfortunately no way to selectively turn off
keyword substitution.  You can use @samp{-ko}
(@pxref{Substitution modes}) to turn off keyword
substitution entirely.

In many cases you can avoid using keywords in
the source, even though they appear in the final
product.  For example, the source for this manual
contains @samp{$@@asis@{@}Author$} whenever the text
@samp{$@splitrcskeyword{Author}$} should appear.  In @code{nroff}
and @code{troff} you can embed the null-character
@code{\&} inside the keyword for a similar effect.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Substitution modes
@section Substitution modes
@cindex Keyword substitution, changing modes
@cindex -k (keyword substitution)
@cindex Kflag

@c FIXME: This could be made more coherent, by expanding it
@c with more examples or something.
Each file has a stored default substitution mode, and
each working directory copy of a file also has a
substitution mode.  The former is set by the @samp{-k}
option to @code{cvs add} and @code{cvs admin}; the
latter is set by the @samp{-k} or @samp{-A} options to @code{cvs
checkout} or @code{cvs update}.
@code{cvs diff} and @code{cvs rdiff} also
have @samp{-k} options.
For some examples,
see @ref{Binary files}, and @ref{Merging and keywords}.
@c The fact that -A is overloaded to mean both reset
@c sticky options and reset sticky tags/dates is
@c somewhat questionable.  Perhaps there should be
@c separate options to reset sticky options (e.g. -k
@c A") and tags/dates (someone suggested -r HEAD could
@c do this instead of setting a sticky tag of "HEAD"
@c as in the status quo but I haven't thought much
@c about that idea.  Of course -r .reset or something
@c could be coined if this needs to be a new option).
@c On the other hand, having -A mean "get things back
@c into the state after a fresh checkout" has a certain
@c appeal, and maybe there is no sufficient reason for
@c creeping featurism in this area.

The modes available are:

@table @samp
@item -kkv
Generate keyword strings using the default form, e.g.
@code{$@splitrcskeyword{Revision}: 5.7 $} for the @code{Revision}
keyword.

@item -kkvl
Like @samp{-kkv}, except that a locker's name is always
inserted if the given revision is currently locked.
The locker's name is only relevant if @code{cvs admin
-l} is in use.

@item -kk
Generate only keyword names in keyword strings; omit
their values.  For example, for the @code{Revision}
keyword, generate the string @code{$@splitrcskeyword{Revision}$}
instead of @code{$@splitrcskeyword{Revision}: 5.7 $}.  This option
is useful to ignore differences due to keyword
substitution when comparing different revisions of a
file (@pxref{Merging and keywords}).

@item -ko
Generate the old keyword string, present in the working
file just before it was checked in.  For example, for
the @code{Revision} keyword, generate the string
@code{$@splitrcskeyword{Revision}: 1.1 $} instead of
@code{$@splitrcskeyword{Revision}: 5.7 $} if that is how the
string appeared when the file was checked in.

@item -kb
Like @samp{-ko}, but also inhibit conversion of line
endings between the canonical form in which they are
stored in the repository (linefeed only), and the form
appropriate to the operating system in use on the
client.  For systems, like unix, which use linefeed
only to terminate lines, this is the same as
@samp{-ko}.  For more information on binary files, see
@ref{Binary files}.

@item -kv
Generate only keyword values for keyword strings.  For
example, for the @code{Revision} keyword, generate the string
@code{5.7} instead of @code{$@splitrcskeyword{Revision}: 5.7 $}.
This can help generate files in programming languages
where it is hard to strip keyword delimiters like
@code{$@splitrcskeyword{Revision}: $} from a string.  However,
further keyword substitution cannot be performed once
the keyword names are removed, so this option should be
used with care.

One often would like to use @samp{-kv} with @code{cvs
export}---@pxref{export}.  But be aware that doesn't
handle an export containing binary files correctly.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Log keyword
@section Problems with the $@splitrcskeyword{Log}$ keyword.

The @code{$@splitrcskeyword{Log}$} keyword is somewhat
controversial.  As long as you are working on your
development system the information is easily accessible
even if you do not use the @code{$@splitrcskeyword{Log}$}
keyword---just do a @code{cvs log}.  Once you export
the file the history information might be useless
anyhow.

A more serious concern is that @sc{cvs} is not good at
handling @code{$@splitrcskeyword{Log}$} entries when a branch is
merged onto the main trunk.  Conflicts often result
from the merging operation.
@c Might want to check whether the CVS implementation
@c of RCS_merge has this problem the same way rcsmerge
@c does.  I would assume so....

People also tend to "fix" the log entries in the file
(correcting spelling mistakes and maybe even factual
errors).  If that is done the information from
@code{cvs log} will not be consistent with the
information inside the file.  This may or may not be a
problem in real life.

It has been suggested that the @code{$@splitrcskeyword{Log}$}
keyword should be inserted @emph{last} in the file, and
not in the files header, if it is to be used at all.
That way the long list of change messages will not
interfere with everyday source file browsing.

@c ---------------------------------------------------------------------
@node Tracking sources
@chapter Tracking third-party sources
@cindex Third-party sources
@cindex Tracking sources

@c FIXME: Need discussion of added and removed files.
@c FIXME: This doesn't really adequately introduce the
@c concepts of "vendor" and "you".  They don't *have*
@c to be separate organizations or separate people.
@c We want a description which is somewhat more based on
@c the technical issues of which sources go where, but
@c also with enough examples of how this relates to
@c relationships like customer-supplier, developer-QA,
@c maintainer-contributor, or whatever, to make it
@c seem concrete.
If you modify a program to better fit your site, you
probably want to include your modifications when the next
release of the program arrives.  @sc{cvs} can help you with
this task.

@cindex Vendor
@cindex Vendor branch
@cindex Branch, vendor-
In the terminology used in @sc{cvs}, the supplier of the
program is called a @dfn{vendor}.  The unmodified
distribution from the vendor is checked in on its own
branch, the @dfn{vendor branch}.  @sc{cvs} reserves branch
1.1.1 for this use.

When you modify the source and commit it, your revision
will end up on the main trunk.  When a new release is
made by the vendor, you commit it on the vendor branch
and copy the modifications onto the main trunk.

Use the @code{import} command to create and update
the vendor branch.  When you import a new file,
the vendor branch is made the `head' revision, so
anyone that checks out a copy of the file gets that
revision.  When a local modification is committed it is
placed on the main trunk, and made the `head'
revision.

@menu
* First import::                Importing for the first time
* Update imports::              Updating with the import command
* Reverting local changes::     Reverting to the latest vendor release
* Binary files in imports::     Binary files require special handling
* Keywords in imports::         Keyword substitution might be undesirable
* Multiple vendor branches::    What if you get sources from several places?
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node First import
@section Importing for the first time
@cindex Importing modules

@c Should mention naming conventions for vendor tags,
@c release tags, and perhaps directory names.
Use the @code{import} command to check in the sources
for the first time.  When you use the @code{import}
command to track third-party sources, the @dfn{vendor
tag} and @dfn{release tags} are useful.  The
@dfn{vendor tag} is a symbolic name for the branch
(which is always 1.1.1, unless you use the @samp{-b
@var{branch}} flag---see @ref{Multiple vendor branches}.).  The
@dfn{release tags} are symbolic names for a particular
release, such as @samp{FSF_0_04}.

@c I'm not completely sure this belongs here.  But
@c we need to say it _somewhere_ reasonably obvious; it
@c is a common misconception among people first learning CVS
Note that @code{import} does @emph{not} change the
directory in which you invoke it.  In particular, it
does not set up that directory as a @sc{cvs} working
directory; if you want to work with the sources import
them first and then check them out into a different
directory (@pxref{Getting the source}).

@cindex wdiff (import example)
Suppose you have the sources to a program called
@code{wdiff} in a directory @file{wdiff-0.04},
and are going to make private modifications that you
want to be able to use even when new releases are made
in the future.  You start by importing the source to
your repository:

@example
$ cd wdiff-0.04
$ cvs import -m "Import of FSF v. 0.04" fsf/wdiff FSF_DIST WDIFF_0_04
@end example

The vendor tag is named @samp{FSF_DIST} in the above
example, and the only release tag assigned is
@samp{WDIFF_0_04}.
@c FIXME: Need to say where fsf/wdiff comes from.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Update imports
@section Updating with the import command

When a new release of the source arrives, you import it into the
repository with the same @code{import} command that you used to set up
the repository in the first place.  The only difference is that you
specify a different release tag this time:

@example
$ tar xfz wdiff-0.05.tar.gz
$ cd wdiff-0.05
$ cvs import -m "Import of FSF v. 0.05" fsf/wdiff FSF_DIST WDIFF_0_05
@end example

@strong{WARNING:  If you use a release tag that already exists in one of the
repository archives, files removed by an import may not be detected.}

For files that have not been modified locally, the newly created
revision becomes the head revision.  If you have made local
changes, @code{import} will warn you that you must merge the changes
into the main trunk, and tell you to use @samp{checkout -j} to do so:

@c FIXME: why "wdiff" here and "fsf/wdiff" in the
@c "import"?  I think the assumption is that one has
@c "wdiff fsf/wdiff" or some such in modules, but it
@c would be better to not use modules in this example.
@example
$ cvs checkout -jFSF_DIST:yesterday -jFSF_DIST wdiff
@end example

@noindent
The above command will check out the latest revision of
@samp{wdiff}, merging the changes made on the vendor branch @samp{FSF_DIST}
since yesterday into the working copy.  If any conflicts arise during
the merge they should be resolved in the normal way (@pxref{Conflicts
example}).  Then, the modified files may be committed.

However, it is much better to use the two release tags rather than using
a date on the branch as suggested above:

@example
$ cvs checkout -jWDIFF_0_04 -jWDIFF_0_05 wdiff
@end example

@noindent
The reason this is better is that
using a date, as suggested above, assumes that you do
not import more than one release of a product per day.
More importantly, using the release tags allows @sc{cvs} to detect files
that were removed between the two vendor releases and mark them for
removal.  Since @code{import} has no way to detect removed files, you
should do a merge like this even if @code{import} doesn't tell you to.

@node Reverting local changes
@section Reverting to the latest vendor release

You can also revert local changes completely and return
to the latest vendor release by changing the `head'
revision back to the vendor branch on all files.  For
example, if you have a checked-out copy of the sources
in @file{~/work.d/wdiff}, and you want to revert to the
vendor's version for all the files in that directory,
you would type:

@example
$ cd ~/work.d/wdiff
$ cvs admin -bFSF_DIST .
@end example

@noindent
You must specify the @samp{-bFSF_DIST} without any space
after the @samp{-b}.  @xref{admin options}.

@node Binary files in imports
@section How to handle binary files with cvs import

Use the @samp{-k} wrapper option to tell import which
files are binary.  @xref{Wrappers}.

@node Keywords in imports
@section How to handle keyword substitution with cvs import

The sources which you are importing may contain
keywords (@pxref{Keyword substitution}).  For example,
the vendor may use @sc{cvs} or some other system
which uses similar keyword expansion syntax.  If you
just import the files in the default fashion, then
the keyword expansions supplied by the vendor will
be replaced by keyword expansions supplied by your
own copy of @sc{cvs}.  It may be more convenient to
maintain the expansions supplied by the vendor, so
that this information can supply information about
the sources that you imported from the vendor.

To maintain the keyword expansions supplied by the
vendor, supply the @samp{-ko} option to @code{cvs
import} the first time you import the file.
This will turn off keyword expansion
for that file entirely, so if you want to be more
selective you'll have to think about what you want
and use the @samp{-k} option to @code{cvs update} or
@code{cvs admin} as appropriate.
@c Supplying -ko to import if the file already existed
@c has no effect.  Not clear to me whether it should
@c or not.

@node Multiple vendor branches
@section Multiple vendor branches

All the examples so far assume that there is only one
vendor from which you are getting sources.  In some
situations you might get sources from a variety of
places.  For example, suppose that you are dealing with
a project where many different people and teams are
modifying the software.  There are a variety of ways to
handle this, but in some cases you have a bunch of
source trees lying around and what you want to do more
than anything else is just to all put them in @sc{cvs} so
that you at least have them in one place.

For handling situations in which there may be more than
one vendor, you may specify the @samp{-b} option to
@code{cvs import}.  It takes as an argument the vendor
branch to import to.  The default is @samp{-b 1.1.1}.

For example, suppose that there are two teams, the red
team and the blue team, that are sending you sources.
You want to import the red team's efforts to branch
1.1.1 and use the vendor tag RED.  You want to import
the blue team's efforts to branch 1.1.3 and use the
vendor tag BLUE.  So the commands you might use are:

@example
$ cvs import dir RED RED_1-0
$ cvs import -b 1.1.3 dir BLUE BLUE_1-5
@end example

Note that if your vendor tag does not match your
@samp{-b} option, @sc{cvs} will not detect this case!  For
example,

@example
$ cvs import -b 1.1.3 dir RED RED_1-0
@end example

@noindent
Be careful; this kind of mismatch is sure to sow
confusion or worse.  I can't think of a useful purpose
for the ability to specify a mismatch here, but if you
discover such a use, don't.  @sc{cvs} is likely to make this
an error in some future release.

@c Probably should say more about the semantics of
@c multiple branches.  What about the default branch?
@c What about joining (perhaps not as useful with
@c multiple branches, or perhaps it is.  Either way
@c should be mentioned).

@c I'm not sure about the best location for this.  In
@c one sense, it might belong right after we've introduced
@c CVS's basic version control model, because people need
@c to figure out builds right away.  The current location
@c is based on the theory that it kind of akin to the
@c "Revision management" section.
@node Builds
@chapter How your build system interacts with CVS
@cindex Builds
@cindex make

As mentioned in the introduction, @sc{cvs} does not
contain software for building your software from source
code.  This section describes how various aspects of
your build system might interact with @sc{cvs}.

@c Is there a way to discuss this without reference to
@c tools other than CVS?  I'm not sure there is; I
@c wouldn't think that people who learn CVS first would
@c even have this concern.
One common question, especially from people who are
accustomed to @sc{rcs}, is how to make their build get
an up to date copy of the sources.  The answer to this
with @sc{cvs} is two-fold.  First of all, since
@sc{cvs} itself can recurse through directories, there
is no need to modify your @file{Makefile} (or whatever
configuration file your build tool uses) to make sure
each file is up to date.  Instead, just use two
commands, first @code{cvs -q update} and then
@code{make} or whatever the command is to invoke your
build tool.  Secondly, you do not necessarily
@emph{want} to get a copy of a change someone else made
until you have finished your own work.  One suggested
approach is to first update your sources, then
implement, build and
test the change you were thinking of, and then commit
your sources (updating first if necessary).  By
periodically (in between changes, using the approach
just described) updating your entire tree, you ensure
that your sources are sufficiently up to date.

@cindex Bill of materials
One common need is to record which versions of which
source files went into a particular build.  This kind
of functionality is sometimes called @dfn{bill of
materials} or something similar.  The best way to do
this with @sc{cvs} is to use the @code{tag} command to
record which versions went into a given build
(@pxref{Tags}).

Using @sc{cvs} in the most straightforward manner
possible, each developer will have a copy of the entire
source tree which is used in a particular build.  If
the source tree is small, or if developers are
geographically dispersed, this is the preferred
solution.  In fact one approach for larger projects is
to break a project down into smaller
@c I say subsystem instead of module because they may or
@c may not use the modules file.
separately-compiled subsystems, and arrange a way of
releasing them internally so that each developer need
check out only those subsystems which they are
actively working on.

Another approach is to set up a structure which allows
developers to have their own copies of some files, and
for other files to access source files from a central
location.  Many people have come up with some such a
@c two such people are paul@sander.cupertino.ca.us (for
@c a previous employer)
@c and gunnar.tornblom@se.abb.com (spicm and related tools),
@c but as far as I know
@c no one has nicely packaged or released such a system (or
@c instructions for constructing one).
system using features such as the symbolic link feature
found in many operating systems, or the @code{VPATH}
feature found in many versions of @code{make}.  One build
tool which is designed to help with this kind of thing
is Odin (see
@code{ftp://ftp.cs.colorado.edu/pub/distribs/odin}).
@c Should we be saying more about Odin?  Or how you use
@c it with CVS?  Also, the Prime Time Freeware for Unix
@c disk (see http://www.ptf.com/) has Odin (with a nice
@c paragraph summarizing it on the web), so that might be a
@c semi-"official" place to point people.
@c
@c Of course, many non-CVS systems have this kind of
@c functionality, for example OSF's ODE
@c (http://www.osf.org/ode/) or mk
@c (http://www.grin.net/~pzi/mk-3.18.4.docs/mk_toc.html
@c He has changed providers in the past; a search engine search
@c for "Peter Ziobrzynski" probably won't get too many
@c spurious hits :-).  A more stable URL might be
@c ftp://ftp.uu.net/pub/cmvc/mk).  But I'm not sure
@c there is any point in mentioning them here unless they
@c can work with CVS.

@c ---------------------------------------------------------------------
@node Special Files
@chapter Special Files

@cindex Special files
@cindex Device nodes
@cindex Ownership, saving in CVS
@cindex Permissions, saving in CVS
@cindex Hard links
@cindex Symbolic links

In normal circumstances, @sc{cvs} works only with regular
files.  Every file in a project is assumed to be
persistent; it must be possible to open, read and close
them; and so on.  @sc{cvs} also ignores file permissions and
ownerships, leaving such issues to be resolved by the
developer at installation time.  In other words, it is
not possible to "check in" a device into a repository;
if the device file cannot be opened, @sc{cvs} will refuse to
handle it.  Files also lose their ownerships and
permissions during repository transactions.

@ignore
If the configuration variable @code{PreservePermissions}
(@pxref{config}) is set in the repository, @sc{cvs} will
save the following file characteristics in the
repository:

@itemize @bullet
@item user and group ownership
@item permissions
@item major and minor device numbers
@item symbolic links
@item hard link structure
@end itemize

Using the @code{PreservePermissions} option affects the
behavior of @sc{cvs} in several ways.  First, some of the
new operations supported by @sc{cvs} are not accessible to
all users.  In particular, file ownership and special
file characteristics may only be changed by the
superuser.  When the @code{PreservePermissions}
configuration variable is set, therefore, users will
have to be `root' in order to perform @sc{cvs} operations.

When @code{PreservePermissions} is in use, some @sc{cvs}
operations (such as @samp{cvs status}) will not
recognize a file's hard link structure, and so will
emit spurious warnings about mismatching hard links.
The reason is that @sc{cvs}'s internal structure does not
make it easy for these operations to collect all the
necessary data about hard links, so they check for file
conflicts with inaccurate data.

A more subtle difference is that @sc{cvs} considers a file
to have changed only if its contents have changed
(specifically, if the modification time of the working
file does not match that of the repository's file).
Therefore, if only the permissions, ownership or hard
linkage have changed, or if a device's major or minor
numbers have changed, @sc{cvs} will not notice.  In order to
commit such a change to the repository, you must force
the commit with @samp{cvs commit -f}.  This also means
that if a file's permissions have changed and the
repository file is newer than the working copy,
performing @samp{cvs update} will silently change the
permissions on the working copy.

Changing hard links in a @sc{cvs} repository is particularly
delicate.  Suppose that file @file{foo} is linked to
file @file{old}, but is later relinked to file
@file{new}.  You can wind up in the unusual situation
where, although @file{foo}, @file{old} and @file{new}
have all had their underlying link patterns changed,
only @file{foo} and @file{new} have been modified, so
@file{old} is not considered a candidate for checking
in.  It can be very easy to produce inconsistent
results this way.  Therefore, we recommend that when it
is important to save hard links in a repository, the
prudent course of action is to @code{touch} any file
whose linkage or status has changed since the last
checkin.  Indeed, it may be wise to @code{touch *}
before each commit in a directory with complex hard
link structures.

It is worth noting that only regular files may
be merged, for reasons that hopefully are obvious.  If
@samp{cvs update} or @samp{cvs checkout -j} attempts to
merge a symbolic link with a regular file, or two
device files for different kinds of devices, @sc{cvs} will
report a conflict and refuse to perform the merge.  At
the same time, @samp{cvs diff} will not report any
differences between these files, since no meaningful
textual comparisons can be made on files which contain
no text.

The @code{PreservePermissions} features do not work
with client/server @sc{cvs}.  Another limitation is
that hard links must be to other files within the same
directory; hard links across directories are not
supported.
@end ignore

@c ---------------------------------------------------------------------
@c ----- START MAN 1 -----
@node CVS commands
@appendix Guide to CVS commands

This appendix describes the overall structure of
@sc{cvs} commands, and describes some commands in
detail (others are described elsewhere; for a quick
reference to @sc{cvs} commands, @pxref{Invoking CVS}).
@c The idea is that we want to move the commands which
@c are described here into the main body of the manual,
@c in the process reorganizing the manual to be
@c organized around what the user wants to do, not
@c organized around CVS commands.
@c
@c Note that many users do expect a manual which is
@c organized by command.  At least some users do.
@c One good addition to the "organized by command"
@c section (if any) would be "see also" links.
@c The awk manual might be a good example; it has a
@c reference manual which is more verbose than Invoking
@c CVS but probably somewhat less verbose than CVS
@c Commands.

@menu
* Structure::                   Overall structure of CVS commands
* Exit status::                 Indicating CVS's success or failure
* ~/.cvsrc::                    Default options with the ~/.cvsrc file
* Global options::              Options you give to the left of cvs_command
* Common options::              Options you give to the right of cvs_command
* add::                         Add files and directories to the repository
* admin::                       Administration
* annotate::                    What revision modified each line of a file?
* checkout::                    Checkout sources for editing
* commit::                      Check files into the repository
* diff::                        Show differences between revisions
* export::                      Export sources from CVS, similar to checkout
* history::                     Show status of files and users
* import::                      Import sources into CVS, using vendor branches
* log::                         Show log messages for files
* rdiff::                       'patch' format diffs between releases
* release::                     Indicate that a directory is no longer in use
* remove::                      Remove files from active development
* update::                      Bring work tree in sync with repository
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Structure
@appendixsec Overall structure of CVS commands
@cindex Structure
@cindex CVS command structure
@cindex Command structure
@cindex Format of CVS commands

The overall format of all @sc{cvs} commands is:

@example
cvs [ cvs_options ] cvs_command [ command_options ] [ command_args ]
@end example

@table @code
@item cvs
The name of the @sc{cvs} program.

@item cvs_options
Some options that affect all sub-commands of @sc{cvs}.  These are
described below.

@item cvs_command
One of several different sub-commands.  Some of the commands have
aliases that can be used instead; those aliases are noted in the
reference manual for that command.  There are only two situations
where you may omit @samp{cvs_command}: @samp{cvs -H} elicits a
list of available commands, and @samp{cvs -v} displays version
information on @sc{cvs} itself.

@item command_options
Options that are specific for the command.

@item command_args
Arguments to the commands.
@end table

There is unfortunately some confusion between
@code{cvs_options} and @code{command_options}.
When given as a @code{cvs_option}, some options only
affect some of the commands.  When given as a
@code{command_option} it may have a different meaning, and
be accepted by more commands.  In other words, do not
take the above categorization too seriously.  Look at
the documentation instead.

@node Exit status
@appendixsec CVS's exit status
@cindex Exit status, of CVS

@sc{cvs} can indicate to the calling environment whether it
succeeded or failed by setting its @dfn{exit status}.
The exact way of testing the exit status will vary from
one operating system to another.  For example in a unix
shell script the @samp{$?} variable will be 0 if the
last command returned a successful exit status, or
greater than 0 if the exit status indicated failure.

If @sc{cvs} is successful, it returns a successful status;
if there is an error, it prints an error message and
returns a failure status.  The one exception to this is
the @code{cvs diff} command.  It will return a
successful status if it found no differences, or a
failure status if there were differences or if there
was an error.  Because this behavior provides no good
way to detect errors, in the future it is possible that
@code{cvs diff} will be changed to behave like the
other @sc{cvs} commands.
@c It might seem like checking whether cvs -q diff
@c produces empty or non-empty output can tell whether
@c there were differences or not.  But it seems like
@c there are cases with output but no differences
@c (testsuite basica-8b).  It is not clear to me how
@c useful it is for a script to be able to check
@c whether there were differences.
@c FIXCVS? In previous versions of CVS, cvs diff
@c returned 0 for no differences, 1 for differences, or
@c 2 for errors.  Is this behavior worth trying to
@c bring back (but what does it mean for VMS?)?

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node ~/.cvsrc
@appendixsec Default options and the ~/.cvsrc file
@cindex .cvsrc file
@cindex Option defaults

There are some @code{command_options} that are used so
often that you might have set up an alias or some other
means to make sure you always specify that option.  One
example (the one that drove the implementation of the
@file{.cvsrc} support, actually) is that many people find the
default output of the @samp{diff} command to be very
hard to read, and that either context diffs or unidiffs
are much easier to understand.

The @file{~/.cvsrc} file is a way that you can add
default options to @code{cvs_commands} within cvs,
instead of relying on aliases or other shell scripts.

The format of the @file{~/.cvsrc} file is simple.  The
file is searched for a line that begins with the same
name as the @code{cvs_command} being executed.  If a
match is found, then the remainder of the line is split
up (at whitespace characters) into separate options and
added to the command arguments @emph{before} any
options from the command line.

If a command has two names (e.g., @code{checkout} and
@code{co}), the official name, not necessarily the one
used on the command line, will be used to match against
the file.  So if this is the contents of the user's
@file{~/.cvsrc} file:

@example
log -N
diff -uN
rdiff -u
update -Pd
checkout -P
release -d
@end example

@noindent
the command @samp{cvs checkout foo} would have the
@samp{-P} option added to the arguments, as well as
@samp{cvs co foo}.

With the example file above, the output from @samp{cvs
diff foobar} will be in unidiff format.  @samp{cvs diff
-c foobar} will provide context diffs, as usual.
Getting "old" format diffs would be slightly more
complicated, because @code{diff} doesn't have an option
to specify use of the "old" format, so you would need
@samp{cvs -f diff foobar}.

In place of the command name you can use @code{cvs} to
specify global options (@pxref{Global options}).  For
example the following line in @file{.cvsrc}

@example
cvs -z6
@end example

@noindent
causes @sc{cvs} to use compression level 6.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Global options
@appendixsec Global options
@cindex Options, global
@cindex Global options
@cindex Left-hand options

The available @samp{cvs_options} (that are given to the
left of @samp{cvs_command}) are:

@table @code
@item --allow-root=@var{rootdir}
Specify legal @sc{cvsroot} directory.  See
@ref{Password authentication server}.

@cindex Authentication, stream
@cindex Stream authentication
@item -a
Authenticate all communication between the client and
the server.  Only has an effect on the @sc{cvs} client.
As of this writing, this is only implemented when using
a GSSAPI connection (@pxref{GSSAPI authenticated}).
Authentication prevents certain sorts of attacks
involving hijacking the active @sc{tcp} connection.
Enabling authentication does not enable encryption.

@cindex RCSBIN, overriding
@cindex Overriding RCSBIN
@item -b @var{bindir}
In @sc{cvs} 1.9.18 and older, this specified that
@sc{rcs} programs are in the @var{bindir} directory.
Current versions of @sc{cvs} do not run @sc{rcs}
programs; for compatibility this option is accepted,
but it does nothing.

@cindex TMPDIR, overriding
@cindex Overriding TMPDIR
@item -T @var{tempdir}
Use @var{tempdir} as the directory where temporary files are
located.  Overrides the setting of the @code{$TMPDIR} environment
variable and any precompiled directory.  This parameter should be
specified as an absolute pathname.
(When running client/server, @samp{-T} affects only the local process;
specifying @samp{-T} for the client has no effect on the server and
vice versa.)

@cindex CVSROOT, overriding
@cindex Overriding CVSROOT
@item -d @var{cvs_root_directory}
Use @var{cvs_root_directory} as the root directory
pathname of the repository.  Overrides the setting of
the @code{$CVSROOT} environment variable.  See @ref{Repository}.

@cindex EDITOR, overriding
@cindex Overriding EDITOR
@item -e @var{editor}
Use @var{editor} to enter revision log information.  Overrides the
setting of the @code{$CVSEDITOR} and @code{$EDITOR}
environment variables.  For more information, see
@ref{Committing your changes}.

@item -f
Do not read the @file{~/.cvsrc} file.  This
option is most often used because of the
non-orthogonality of the @sc{cvs} option set.  For
example, the @samp{cvs log} option @samp{-N} (turn off
display of tag names) does not have a corresponding
option to turn the display on.  So if you have
@samp{-N} in the @file{~/.cvsrc} entry for @samp{log},
you may need to use @samp{-f} to show the tag names.

@item -H
@itemx --help
Display usage information about the specified @samp{cvs_command}
(but do not actually execute the command).  If you don't specify
a command name, @samp{cvs -H} displays overall help for
@sc{cvs}, including a list of other help options.
@c It seems to me it is better to document it this way
@c rather than trying to update this documentation
@c every time that we add a --help-foo option.  But
@c perhaps that is confusing...

@cindex Read-only mode
@item -n
Do not change any files.  Attempt to execute the
@samp{cvs_command}, but only to issue reports; do not remove,
update, or merge any existing files, or create any new files.

Note that @sc{cvs} will not necessarily produce exactly
the same output as without @samp{-n}.  In some cases
the output will be the same, but in other cases
@sc{cvs} will skip some of the processing that would
have been required to produce the exact same output.

@item -Q
Cause the command to be really quiet; the command will only
generate output for serious problems.

@item -q
Cause the command to be somewhat quiet; informational messages,
such as reports of recursion through subdirectories, are
suppressed.

@cindex Read-only files, and -r
@item -r
Make new working files read-only.  Same effect
as if the @code{$CVSREAD} environment variable is set
(@pxref{Environment variables}).  The default is to
make working files writable, unless watches are on
(@pxref{Watches}).

@item -s @var{variable}=@var{value}
Set a user variable (@pxref{Variables}).

@cindex Trace
@item -t
Trace program execution; display messages showing the steps of
@sc{cvs} activity.  Particularly useful with @samp{-n} to explore the
potential impact of an unfamiliar command.

@item -v
@item --version
Display version and copyright information for @sc{cvs}.

@cindex CVSREAD, overriding
@cindex Overriding CVSREAD
@item -w
Make new working files read-write.  Overrides the
setting of the @code{$CVSREAD} environment variable.
Files are created read-write by default, unless @code{$CVSREAD} is
set or @samp{-r} is given.
@c Note that -w only overrides -r and CVSREAD; it has
@c no effect on files which are readonly because of
@c "cvs watch on".  My guess is that is the way it
@c should be (or should "cvs -w get" on a watched file
@c be the same as a get and a cvs edit?), but I'm not
@c completely sure whether to document it this way.

@item -x
@cindex Encryption
Encrypt all communication between the client and the
server.  Only has an effect on the @sc{cvs} client.  As
of this writing, this is only implemented when using a
GSSAPI connection (@pxref{GSSAPI authenticated}) or a
Kerberos connection (@pxref{Kerberos authenticated}).
Enabling encryption implies that message traffic is
also authenticated.  Encryption support is not
available by default; it must be enabled using a
special configure option, @file{--enable-encryption},
when you build @sc{cvs}.

@item -z @var{gzip-level}
@cindex Compression
@cindex Gzip
Set the compression level.
Valid levels are 1 (high speed, low compression) to
9 (low speed, high compression), or 0 to disable
compression (the default).
Only has an effect on the @sc{cvs} client.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Common options
@appendixsec Common command options
@cindex Common options
@cindex Right-hand options

This section describes the @samp{command_options} that
are available across several @sc{cvs} commands.  These
options are always given to the right of
@samp{cvs_command}. Not all
commands support all of these options; each option is
only supported for commands where it makes sense.
However, when a command has one of these options you
can almost always count on the same behavior of the
option as in other commands.  (Other command options,
which are listed with the individual commands, may have
different behavior from one @sc{cvs} command to the other).

@strong{The @samp{history} command is an exception; it supports
many options that conflict even with these standard options.}

@table @code
@cindex Dates
@cindex Time
@cindex Specifying dates
@item -D @var{date_spec}
Use the most recent revision no later than @var{date_spec}.
@var{date_spec} is a single argument, a date description
specifying a date in the past.

The specification is @dfn{sticky} when you use it to make a
private copy of a source file; that is, when you get a working
file using @samp{-D}, @sc{cvs} records the date you specified, so that
further updates in the same directory will use the same date
(for more information on sticky tags/dates, @pxref{Sticky tags}).

@samp{-D} is available with the @code{annotate}, @code{checkout},
@code{diff}, @code{export}, @code{history},
@code{rdiff}, @code{rtag}, and @code{update} commands.
(The @code{history} command uses this option in a
slightly different way; @pxref{history options}).

@c What other formats should we accept?  I don't want
@c to start accepting a whole mess of non-standard
@c new formats (there are a lot which are in wide use in
@c one context or another), but practicality does
@c dictate some level of flexibility.
@c * POSIX.2 (e.g. touch, ls output, date) and other
@c POSIX and/or de facto unix standards (e.g. at).  The
@c practice here is too inconsistent to be of any use.
@c * VMS dates.  This is not a formal standard, but
@c there is a published specification (see SYS$ASCTIM
@c and SYS$BINTIM in the _VMS System Services Reference
@c Manual_), it is implemented consistently in VMS
@c utilities, and VMS users will expect CVS running on
@c VMS to support this format (and if we're going to do
@c that, better to make CVS support it on all
@c platforms.  Maybe).
@c
@c NOTE: The tar manual has some documentation for
@c getdate.y (just for our info; we don't want to
@c attempt to document all the formats accepted by
@c getdate.y).
@c
@c One more note: In output, CVS should consistently
@c use one date format, and that format should be one that
@c it accepts in input as well.  The former isn't
@c really true (see survey below), and I'm not
@c sure that either of those formats is accepted in
@c input.
@c
@c cvs log
@c   current 1996/01/02 13:45:31
@c   Internet 02 Jan 1996 13:45:31 UT
@c   ISO 1996-01-02 13:45:31
@c cvs ann
@c   current 02-Jan-96
@c   Internet-like 02 Jan 96
@c   ISO 96-01-02
@c cvs status
@c   current Tue Jun 11 02:54:53 1996
@c   Internet [Tue,] 11 Jun 1996 02:54:53
@c   ISO 1996-06-11 02:54:53
@c   note: date possibly should be omitted entirely for
@c   other reasons.
@c cvs editors
@c   current Tue Jun 11 02:54:53 1996 GMT
@c cvs history
@c   current 06/11 02:54 +0000
@c any others?
@c There is a good chance the proper solution has to
@c involve at least some level of letting the user
@c decide which format (with the default being the
@c formats CVS has always used; changing these might be
@c _very_ disruptive since scripts may very well be
@c parsing them).
@c
@c Another random bit of prior art concerning dates is
@c the strptime function which takes templates such as
@c "%m/%d/%y", and apparent a variant of getdate()
@c which also honors them.  See
@c X/Open CAE Specification, System Interfaces and
@c Headers Issue 4, Version 2 (September 1994), in the
@c entry for getdate() on page 231

@cindex Timezone, in input
@cindex Zone, time, in input
A wide variety of date formats are supported by
@sc{cvs}.  The most standard ones are ISO8601 (from the
International Standards Organization) and the Internet
e-mail standard (specified in RFC822 as amended by
RFC1123).

@c Probably should be doing more to spell out just what
@c the rules are, rather than just giving examples.
@c But I want to keep this simple too.
@c So I don't know....
@c A few specific issues: (1) Maybe should reassure
@c people that years after 2000
@c work (they are in the testsuite, so they do indeed
@c work).  (2) What do two digit years
@c mean?  Where do we accept them?  (3) Local times can
@c be ambiguous or nonexistent if they fall during the
@c hour when daylight savings time goes into or out of
@c effect.  Pretty obscure, so I'm not at all sure we
@c should be documenting the behavior in that case.
ISO8601 dates have many variants but a few examples
are:

@example
1972-09-24
1972-09-24 20:05
@end example
@c I doubt we really accept all ISO8601 format dates
@c (for example, decimal hours like 1972-09-24 20,2)
@c I'm not sure we should, many of them are pretty
@c bizarre and it has lots of gratuitous multiple ways
@c to specify the same thing.

There are a lot more ISO8601 date formats, and @sc{cvs}
accepts many of them, but you probably don't want to
hear the @emph{whole} long story :-).

@c Citing a URL here is kind of problematic given how
@c much they change and people who have old versions of
@c this manual, but in case we want to reinstate an
@c ISO8601 URL, a few are:
@c http://www.saqqara.demon.co.uk/datefmt.htm
@c http://www.cl.cam.ac.uk/~mgk25/iso-time.html
@c Citing some other ISO8601 source is probably even
@c worse :-).

In addition to the dates allowed in Internet e-mail
itself, @sc{cvs} also allows some of the fields to be
omitted.  For example:
@c FIXME: Need to figure out better, and document,
@c what we want to allow the user to omit.
@c NOTE: "omit" does not imply "reorder".
@c FIXME: Need to cite a web page describing how to get
@c RFC's.

@example
24 Sep 1972 20:05
24 Sep
@end example

The date is interpreted as being in the
local timezone, unless a specific timezone is
specified.

These two date formats are preferred.  However,
@sc{cvs} currently accepts a wide variety of other date
formats.  They are intentionally not documented here in
any detail, and future versions of @sc{cvs} might not
accept all of them.
@c We should document and testsuite "now" and
@c "yesterday".  "now" is mentioned in the FAQ and
@c "yesterday" is mentioned in this document (and the
@c message from "cvs import" suggesting a merge
@c command).  What else?  Probably some/all of the "3
@c weeks ago" family.
@c
@c Maybe at
@c some point have CVS start give warnings on "unofficial"
@c formats (many of which might be typos or user
@c misunderstandings, and/or formats people never/rarely
@c use to specify dates)?

One such format is
@code{@var{month}/@var{day}/@var{year}}.  This may
confuse people who are accustomed to having the month
and day in the other order; @samp{1/4/96} is January 4,
not April 1.

Remember to quote the argument to the @samp{-D}
flag so that your shell doesn't interpret spaces as
argument separators.  A command using the @samp{-D}
flag can look like this:

@example
$ cvs diff -D "1 hour ago" cvs.texinfo
@end example

@cindex Forcing a tag match
@item -f
When you specify a particular date or tag to @sc{cvs} commands, they
normally ignore files that do not contain the tag (or did not
exist prior to the date) that you specified.  Use the @samp{-f} option
if you want files retrieved even when there is no match for the
tag or date.  (The most recent revision of the file
will be used).

Note that even with @samp{-f}, a tag that you specify
must exist (that is, in some file, not necessary in
every file).  This is so that @sc{cvs} will continue to
give an error if you mistype a tag name.

@need 800
@samp{-f} is available with these commands:
@code{annotate}, @code{checkout}, @code{export},
@code{rdiff}, @code{rtag}, and @code{update}.

@strong{WARNING:  The @code{commit} and @code{remove}
commands also have a
@samp{-f} option, but it has a different behavior for
those commands.  See @ref{commit options}, and
@ref{Removing files}.}

@item -k @var{kflag}
Alter the default processing of keywords.
See @ref{Keyword substitution}, for the meaning of
@var{kflag}.  Your @var{kflag} specification is
@dfn{sticky} when you use it to create a private copy
of a source file; that is, when you use this option
with the @code{checkout} or @code{update} commands,
@sc{cvs} associates your selected @var{kflag} with the
file, and continues to use it with future update
commands on the same file until you specify otherwise.

The @samp{-k} option is available with the @code{add},
@code{checkout}, @code{diff}, @code{rdiff}, @code{import} and
@code{update} commands.

@item -l
Local; run only in current working directory, rather than
recursing through subdirectories.

Available with the following commands: @code{annotate}, @code{checkout},
@code{commit}, @code{diff}, @code{edit}, @code{editors}, @code{export},
@code{log}, @code{rdiff}, @code{remove}, @code{rtag},
@code{status}, @code{tag}, @code{unedit}, @code{update}, @code{watch},
and @code{watchers}.

@cindex Editor, avoiding invocation of
@cindex Avoiding editor invocation
@item -m @var{message}
Use @var{message} as log information, instead of
invoking an editor.

Available with the following commands: @code{add},
@code{commit} and @code{import}.

@item -n
Do not run any tag program.  (A program can be
specified to run in the modules
database (@pxref{modules}); this option bypasses it).

@strong{This is not the same as the @samp{cvs -n}
program option, which you can specify to the left of a cvs command!}

Available with the @code{checkout}, @code{export},
and @code{rtag} commands.

@item -P
Prune empty directories.  See @ref{Removing directories}.

@item -p
Pipe the files retrieved from the repository to standard output,
rather than writing them in the current directory.  Available
with the @code{checkout} and @code{update} commands.

@item -R
Process directories recursively.  This is on by default.

Available with the following commands: @code{annotate}, @code{checkout},
@code{commit}, @code{diff}, @code{edit}, @code{editors}, @code{export},
@code{rdiff}, @code{remove}, @code{rtag},
@code{status}, @code{tag}, @code{unedit}, @code{update}, @code{watch},
and @code{watchers}.

@item -r @var{tag}
@cindex HEAD, special tag
@cindex BASE, special tag
Use the revision specified by the @var{tag} argument instead of the
default @dfn{head} revision.  As well as arbitrary tags defined
with the @code{tag} or @code{rtag} command, two special tags are
always available: @samp{HEAD} refers to the most recent version
available in the repository, and @samp{BASE} refers to the
revision you last checked out into the current working directory.

@c FIXME: What does HEAD really mean?  I believe that
@c the current answer is the head of the default branch
@c for all cvs commands except diff.  For diff, it
@c seems to be (a) the head of the trunk (or the default
@c branch?) if there is no sticky tag, (b) the head of the
@c branch for the sticky tag, if there is a sticky tag.
@c (b) is ugly as it differs
@c from what HEAD means for other commands, but people
@c and/or scripts are quite possibly used to it.
@c See "head" tests in sanity.sh.
@c Probably the best fix is to introduce two new
@c special tags, ".thead" for the head of the trunk,
@c and ".bhead" for the head of the current branch.
@c Then deprecate HEAD.  This has the advantage of
@c not surprising people with a change to HEAD, and a
@c side benefit of also phasing out the poorly-named
@c HEAD (see discussion of reserved tag names in node
@c "Tags").  Of course, .thead and .bhead should be
@c carefully implemented (with the implementation the
@c same for "diff" as for everyone else), test cases
@c written (similar to the ones in "head"), new tests
@c cases written for things like default branches, &c.

The tag specification is sticky when you use this
@c option
with @code{checkout} or @code{update} to make your own
copy of a file: @sc{cvs} remembers the tag and continues to use it on
future update commands, until you specify otherwise (for more information
on sticky tags/dates, @pxref{Sticky tags}).

The tag can be either a symbolic or numeric tag, as
described in @ref{Tags}, or the name of a branch, as
described in @ref{Branching and merging}.
When a command expects a specific revision,
the name of a branch is interpreted as the most recent
revision on that branch.

Specifying the @samp{-q} global option along with the
@samp{-r} command option is often useful, to suppress
the warning messages when the @sc{rcs} file
does not contain the specified tag.

@strong{This is not the same as the overall @samp{cvs -r} option,
which you can specify to the left of a @sc{cvs} command!}

@samp{-r} is available with the @code{annotate}, @code{checkout},
@code{commit}, @code{diff}, @code{history}, @code{export}, @code{rdiff}, 
@code{rtag}, and @code{update} commands.

@item -W
Specify file names that should be filtered.  You can
use this option repeatedly.  The spec can be a file
name pattern of the same type that you can specify in
the @file{.cvswrappers} file.
Available with the following commands: @code{import},
and @code{update}.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node add
@appendixsec add---Add files and directories to the repository
@cindex add (subcommand)

@itemize @bullet
@item
Synopsis: add [-k rcs-kflag] [-m message] files...
@item
Requires: repository, working directory.
@item
Changes: repository, working directory.
@end itemize

The @code{add} command is used to present new files
and directories for addition into the @sc{cvs}
repository.  When @code{add} is used on a directory,
a new directory is created in the repository
immediately.  When used on a file, only the working
directory is updated.  Changes to the repository are
not made until the @code{commit} command is used on
the newly added file. 

The @code{add} command also resurrects files that
have been previously removed.  This can be done
before or after the @code{commit} command is used
to finalize the removal of files.  Resurrected files
are restored into the working directory at the time
the @code{add} command is executed.

@menu
* add options::             add options
* add examples::            add examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node add options
@appendixsubsec add options

These standard options are supported by @code{add}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -k @var{kflag}
Process keywords according to @var{kflag}.  See
@ref{Keyword substitution}.
This option is sticky; future updates of
this file in this working directory will use the same
@var{kflag}.  The @code{status} command can be viewed
to see the sticky options.  For more information on
the @code{status} command, @xref{Invoking CVS}.

@item -m @var{message}
Use @var{message} as the log message, instead of
invoking an editor.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node add examples
@appendixsubsec add examples

@appendixsubsubsec Adding a directory

@example
$ mkdir doc
$ cvs add doc
Directory /path/to/repository/doc added to the repository
@end example

@appendixsubsubsec Adding a file

@example

$ >TODO
$ cvs add TODO
cvs add: scheduling file `TODO' for addition
cvs add: use 'cvs commit' to add this file permanently
@end example

@appendixsubsubsec Undoing a @code{remove} command

@example
$ rm -f makefile
$ cvs remove makefile
cvs remove: scheduling `makefile' for removal
cvs remove: use 'cvs commit' to remove this file permanently
$ cvs add makefile
U makefile
cvs add: makefile, version 1.2, resurrected
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node admin
@appendixsec admin---Administration
@cindex Admin (subcommand)

@itemize @bullet
@item
Requires: repository, working directory.
@item
Changes: repository.
@item
Synonym: rcs
@end itemize

This is the @sc{cvs} interface to assorted
administrative facilities.  Some of them have
questionable usefulness for @sc{cvs} but exist for
historical purposes.  Some of the questionable options
are likely to disappear in the future.  This command
@emph{does} work recursively, so extreme care should be
used.

@cindex cvsadmin
On unix, if there is a group named @code{cvsadmin},
only members of that group can run @code{cvs admin}
(except for the @code{cvs admin -k} command, which can
be run by anybody).  This group should exist on the
server, or any system running the non-client/server
@sc{cvs}.  To disallow @code{cvs admin} for all users,
create a group with no users in it.  On NT, the
@code{cvsadmin} feature does not exist and all users
can run @code{cvs admin}.

@menu
* admin options::               admin options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node admin options
@appendixsubsec admin options

Some of these options have questionable usefulness for
@sc{cvs} but exist for historical purposes.  Some even
make it impossible to use @sc{cvs} until you undo the
effect!

@table @code
@item -A@var{oldfile}
Might not work together with @sc{cvs}.  Append the
access list of @var{oldfile} to the access list of the
@sc{rcs} file.

@item -a@var{logins}
Might not work together with @sc{cvs}.  Append the
login names appearing in the comma-separated list
@var{logins} to the access list of the @sc{rcs} file.

@item -b[@var{rev}]
Set the default branch to @var{rev}.  In @sc{cvs}, you
normally do not manipulate default branches; sticky
tags (@pxref{Sticky tags}) are a better way to decide
which branch you want to work on.  There is one reason
to run @code{cvs admin -b}: to revert to the vendor's
version when using vendor branches (@pxref{Reverting
local changes}).
There can be no space between @samp{-b} and its argument.
@c Hmm, we don't document the usage where rev is
@c omitted.  Maybe that usage can/should be deprecated
@c (and replaced with -bHEAD or something?) (so we can toss
@c the optional argument).  Note that -bHEAD does not
@c work, as of 17 Sep 1997, but probably will once "cvs
@c admin" is internal to CVS.

@cindex Comment leader
@item -c@var{string}
Sets the comment leader to @var{string}.  The comment
leader is not used by current versions of @sc{cvs} or
@sc{rcs} 5.7.  Therefore, you can almost surely not
worry about it.  See @ref{Keyword substitution}.

@item -e[@var{logins}]
Might not work together with @sc{cvs}.  Erase the login
names appearing in the comma-separated list
@var{logins} from the access list of the RCS file.  If
@var{logins} is omitted, erase the entire access list.
There can be no space between @samp{-e} and its argument.

@item -I
Run interactively, even if the standard input is not a
terminal.  This option does not work with the
client/server @sc{cvs} and is likely to disappear in
a future release of @sc{cvs}.

@item -i
Useless with @sc{cvs}.  This creates and initializes a
new @sc{rcs} file, without depositing a revision.  With
@sc{cvs}, add files with the @code{cvs add} command
(@pxref{Adding files}).

@item -k@var{subst}
Set the default keyword
substitution to @var{subst}.  See @ref{Keyword
substitution}.  Giving an explicit @samp{-k} option to
@code{cvs update}, @code{cvs export}, or @code{cvs
checkout} overrides this default.

@item -l[@var{rev}]
Lock the revision with number @var{rev}.  If a branch
is given, lock the latest revision on that branch.  If
@var{rev} is omitted, lock the latest revision on the
default branch.  There can be no space between
@samp{-l} and its argument.

This can be used in conjunction with the
@file{rcslock.pl} script in the @file{contrib}
directory of the @sc{cvs} source distribution to
provide reserved checkouts (where only one user can be
editing a given file at a time).  See the comments in
that file for details (and see the @file{README} file
in that directory for disclaimers about the unsupported
nature of contrib).  According to comments in that
file, locking must set to strict (which is the default).

@item -L
Set locking to strict.  Strict locking means that the
owner of an RCS file is not exempt from locking for
checkin.  For use with @sc{cvs}, strict locking must be
set; see the discussion under the @samp{-l} option above.

@cindex Changing a log message
@cindex Replacing a log message
@cindex Correcting a log message
@cindex Fixing a log message
@cindex Log message, correcting
@item -m@var{rev}:@var{msg}
Replace the log message of revision @var{rev} with
@var{msg}.

@c The rcs -M option, to suppress sending mail, has never been
@c documented as a cvs admin option.

@item -N@var{name}[:[@var{rev}]]
Act like @samp{-n}, except override any previous
assignment of @var{name}.  For use with magic branches,
see @ref{Magic branch numbers}.

@item -n@var{name}[:[@var{rev}]]
Associate the symbolic name @var{name} with the branch
or revision @var{rev}.  It is normally better to use
@samp{cvs tag} or @samp{cvs rtag} instead.  Delete the
symbolic name if both @samp{:} and @var{rev} are
omitted; otherwise, print an error message if
@var{name} is already associated with another number.
If @var{rev} is symbolic, it is expanded before
association.  A @var{rev} consisting of a branch number
followed by a @samp{.} stands for the current latest
revision in the branch.  A @samp{:} with an empty
@var{rev} stands for the current latest revision on the
default branch, normally the trunk.  For example,
@samp{cvs admin -n@var{name}:} associates @var{name} with the
current latest revision of all the RCS files;
this contrasts with @samp{cvs admin -n@var{name}:$} which
associates @var{name} with the revision numbers
extracted from keyword strings in the corresponding
working files.

@cindex Deleting revisions
@cindex Outdating revisions
@cindex Saving space
@item -o@var{range}
Deletes (@dfn{outdates}) the revisions given by
@var{range}.

Note that this command can be quite dangerous unless
you know @emph{exactly} what you are doing (for example
see the warnings below about how the
@var{rev1}:@var{rev2} syntax is confusing).

If you are short on disc this option might help you.
But think twice before using it---there is no way short
of restoring the latest backup to undo this command!
If you delete different revisions than you planned,
either due to carelessness or (heaven forbid) a @sc{cvs}
bug, there is no opportunity to correct the error
before the revisions are deleted.  It probably would be
a good idea to experiment on a copy of the repository
first.

Specify @var{range} in one of the following ways:

@table @code
@item @var{rev1}::@var{rev2}
Collapse all revisions between rev1 and rev2, so that
@sc{cvs} only stores the differences associated with going
from rev1 to rev2, not intermediate steps.  For
example, after @samp{-o 1.3::1.5} one can retrieve
revision 1.3, revision 1.5, or the differences to get
from 1.3 to 1.5, but not the revision 1.4, or the
differences between 1.3 and 1.4.  Other examples:
@samp{-o 1.3::1.4} and @samp{-o 1.3::1.3} have no
effect, because there are no intermediate revisions to
remove.

@item ::@var{rev}
Collapse revisions between the beginning of the branch
containing @var{rev} and @var{rev} itself.  The
branchpoint and @var{rev} are left intact.  For
example, @samp{-o ::1.3.2.6} deletes revision 1.3.2.1,
revision 1.3.2.5, and everything in between, but leaves
1.3 and 1.3.2.6 intact.

@item @var{rev}::
Collapse revisions between @var{rev} and the end of the
branch containing @var{rev}.  Revision @var{rev} is
left intact but the head revision is deleted.

@item @var{rev}
Delete the revision @var{rev}.  For example, @samp{-o
1.3} is equivalent to @samp{-o 1.2::1.4}.

@item @var{rev1}:@var{rev2}
Delete the revisions from @var{rev1} to @var{rev2},
inclusive, on the same branch.  One will not be able to
retrieve @var{rev1} or @var{rev2} or any of the
revisions in between.  For example, the command
@samp{cvs admin -oR_1_01:R_1_02 .} is rarely useful.
It means to delete revisions up to, and including, the
tag R_1_02.  But beware!  If there are files that have not
changed between R_1_02 and R_1_03 the file will have
@emph{the same} numerical revision number assigned to
the tags R_1_02 and R_1_03.  So not only will it be
impossible to retrieve R_1_02; R_1_03 will also have to
be restored from the tapes!  In most cases you want to
specify @var{rev1}::@var{rev2} instead.

@item :@var{rev}
Delete revisions from the beginning of the
branch containing @var{rev} up to and including
@var{rev}.

@item @var{rev}:
Delete revisions from revision @var{rev}, including
@var{rev} itself, to the end of the branch containing
@var{rev}.
@end table

None of the revisions to be deleted may have
branches or locks.

If any of the revisions to be deleted have symbolic
names, and one specifies one of the @samp{::} syntaxes,
then @sc{cvs} will give an error and not delete any
revisions.  If you really want to delete both the
symbolic names and the revisions, first delete the
symbolic names with @code{cvs tag -d}, then run
@code{cvs admin -o}.  If one specifies the
non-@samp{::} syntaxes, then @sc{cvs} will delete the
revisions but leave the symbolic names pointing to
nonexistent revisions.  This behavior is preserved for
compatibility with previous versions of @sc{cvs}, but
because it isn't very useful, in the future it may
change to be like the @samp{::} case.

Due to the way @sc{cvs} handles branches @var{rev}
cannot be specified symbolically if it is a branch.
See @ref{Magic branch numbers} for an explanation.
@c FIXME: is this still true?  I suspect not.

Make sure that no-one has checked out a copy of the
revision you outdate.  Strange things will happen if he
starts to edit it and tries to check it back in.  For
this reason, this option is not a good way to take back
a bogus commit; commit a new revision undoing the bogus
change instead (@pxref{Merging two revisions}).

@item -q
Run quietly; do not print diagnostics.

@item -s@var{state}[:@var{rev}]
Useful with @sc{cvs}.  Set the state attribute of the
revision @var{rev} to @var{state}.  If @var{rev} is a
branch number, assume the latest revision on that
branch.  If @var{rev} is omitted, assume the latest
revision on the default branch.  Any identifier is
acceptable for @var{state}.  A useful set of states is
@samp{Exp} (for experimental), @samp{Stab} (for
stable), and @samp{Rel} (for released).  By default,
the state of a new revision is set to @samp{Exp} when
it is created.  The state is visible in the output from
@var{cvs log} (@pxref{log}), and in the
@samp{$@splitrcskeyword{Log}$} and @samp{$@splitrcskeyword{State}$} keywords
(@pxref{Keyword substitution}).  Note that @sc{cvs}
uses the @code{dead} state for its own purposes (@pxref{Attic}); to
take a file to or from the @code{dead} state use
commands like @code{cvs remove} and @code{cvs add}
(@pxref{Adding and removing}), not @code{cvs admin -s}.

@item -t[@var{file}]
Useful with @sc{cvs}.  Write descriptive text from the
contents of the named @var{file} into the RCS file,
deleting the existing text.  The @var{file} pathname
may not begin with @samp{-}.  The descriptive text can be seen in the
output from @samp{cvs log} (@pxref{log}).
There can be no space between @samp{-t} and its argument.

If @var{file} is omitted,
obtain the text from standard input, terminated by
end-of-file or by a line containing @samp{.} by itself.
Prompt for the text if interaction is possible; see
@samp{-I}.

@item -t-@var{string}
Similar to @samp{-t@var{file}}. Write descriptive text
from the @var{string} into the @sc{rcs} file, deleting
the existing text.
There can be no space between @samp{-t} and its argument.

@c The rcs -T option, do not update last-mod time for
@c minor changes, has never been documented as a
@c cvs admin option.

@item -U
Set locking to non-strict.  Non-strict locking means
that the owner of a file need not lock a revision for
checkin.  For use with @sc{cvs}, strict locking must be
set; see the discussion under the @samp{-l} option
above.

@item -u[@var{rev}]
See the option @samp{-l} above, for a discussion of
using this option with @sc{cvs}.  Unlock the revision
with number @var{rev}.  If a branch is given, unlock
the latest revision on that branch.  If @var{rev} is
omitted, remove the latest lock held by the caller.
Normally, only the locker of a revision may unlock it;
somebody else unlocking a revision breaks the lock.
This causes the original locker to be sent a @code{commit}
notification (@pxref{Getting Notified}).
There can be no space between @samp{-u} and its argument.

@item -V@var{n}
In previous versions of @sc{cvs}, this option meant to
write an @sc{rcs} file which would be acceptable to
@sc{rcs} version @var{n}, but it is now obsolete and
specifying it will produce an error.
@c Note that -V without an argument has never been
@c documented as a cvs admin option.

@item -x@var{suffixes}
In previous versions of @sc{cvs}, this was documented
as a way of specifying the names of the @sc{rcs}
files.  However, @sc{cvs} has always required that the
@sc{rcs} files used by @sc{cvs} end in @samp{,v}, so
this option has never done anything useful.

@c The rcs -z option, to specify the timezone, has
@c never been documented as a cvs admin option.
@end table


@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node annotate
@appendixsec annotate---What revision modified each line of a file?
@cindex annotate (subcommand)

@itemize @bullet
@item
Synopsis: annotate [options] files@dots{}
@item
Requires: repository.
@item
Synonym: blame
@item
Changes: nothing.
@end itemize

For each file in @var{files}, print the head revision
of the trunk, together with information on the last
modification for each line.  

@menu
* annotate options::            annotate options
* annotate example::            annotate example
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node annotate options
@appendixsubsec annotate options

These standard options are supported by @code{annotate}
(@pxref{Common options} for a complete description of
them):

@table @code
@item -l
Local directory only, no recursion.

@item -R
Process directories recursively.

@item -f
Use head revision if tag/date not found.

@item -F
Annotate binary files.

@item -r @var{revision}
Annotate file as of specified revision/tag.

@item -D @var{date}
Annotate file as of specified date.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node annotate example
@appendixsubsec annotate example

For example:

@example
$ cvs annotate ssfile
Annotations for ssfile
***************
1.1          (mary     27-Mar-96): ssfile line 1
1.2          (joe      28-Mar-96): ssfile line 2
@end example

The file @file{ssfile} currently contains two lines.
The @code{ssfile line 1} line was checked in by
@code{mary} on March 27.  Then, on March 28, @code{joe}
added a line @code{ssfile line 2}, without modifying
the @code{ssfile line 1} line.  This report doesn't
tell you anything about lines which have been deleted
or replaced; you need to use @code{cvs diff} for that
(@pxref{diff}).

The options to @code{cvs annotate} are listed in
@ref{Invoking CVS}, and can be used to select the files
and revisions to annotate.  The options are described
in more detail there and in @ref{Common options}.

@c FIXME: maybe an example using the options?  Just
@c what it means to select a revision might be worth a
@c few words of explanation ("you want to see who
@c changed this line *before* 1.4"...).


@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node checkout
@appendixsec checkout---Check out sources for editing
@cindex checkout (subcommand)
@cindex co (subcommand)

@itemize @bullet
@item
Synopsis: checkout [options] modules@dots{}
@item
Requires: repository.
@item
Changes: working directory.
@item
Synonyms: co, get
@end itemize

Create or update a working directory containing copies of the
source files specified by @var{modules}.  You must execute
@code{checkout} before using most of the other @sc{cvs}
commands, since most of them operate on your working
directory.

The @var{modules} are either
symbolic names for some
collection of source directories and files, or paths to
directories or files in the repository.  The symbolic
names are defined in the @samp{modules} file.
See @ref{modules}.
@c Needs an example, particularly of the non-"modules"
@c case but probably of both.

@c FIXME: this seems like a very odd place to introduce
@c people to how CVS works.  The bit about unreserved
@c checkouts is also misleading as it depends on how
@c things are set up.
Depending on the modules you specify, @code{checkout} may
recursively create directories and populate them with
the appropriate source files.  You can then edit these
source files at any time (regardless of whether other
software developers are editing their own copies of the
sources); update them to include new changes applied by
others to the source repository; or commit your work as
a permanent change to the source repository.

Note that @code{checkout} is used to create
directories.  The top-level directory created is always
added to the directory where @code{checkout} is
invoked, and usually has the same name as the specified
module.  In the case of a module alias, the created
sub-directory may have a different name, but you can be
sure that it will be a sub-directory, and that
@code{checkout} will show the relative path leading to
each file as it is extracted into your private work
area (unless you specify the @samp{-Q} global option).

The files created by @code{checkout} are created
read-write, unless the @samp{-r} option to @sc{cvs}
(@pxref{Global options}) is specified, the
@code{CVSREAD} environment variable is specified
(@pxref{Environment variables}), or a watch is in
effect for that file (@pxref{Watches}).

Note that running @code{checkout} on a directory that was already
built by a prior @code{checkout} is also permitted.
This is similar to specifying the @samp{-d} option
to the @code{update} command in the sense that new
directories that have been created in the repository
will appear in your work area.
However, @code{checkout} takes a module name whereas
@code{update} takes a directory name.  Also
to use @code{checkout} this way it must be run from the
top level directory (where you originally ran
@code{checkout} from), so before you run
@code{checkout} to update an existing directory, don't
forget to change your directory to the top level
directory.

For the output produced by the @code{checkout} command,
@xref{update output}.

@menu
* checkout options::            checkout options
* checkout examples::           checkout examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node checkout options
@appendixsubsec checkout options

These standard options are supported by @code{checkout}
(@pxref{Common options} for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.
This option is sticky, and implies @samp{-P}.  See
@ref{Sticky tags} for more information on sticky tags/dates.

@item -f
Only useful with the @samp{-D @var{date}} or @samp{-r
@var{tag}} flags.  If no matching revision is found,
retrieve the most recent revision (instead of ignoring
the file).

@item -k @var{kflag}
Process keywords according to @var{kflag}.  See
@ref{Keyword substitution}.
This option is sticky; future updates of
this file in this working directory will use the same
@var{kflag}.  The @code{status} command can be viewed
to see the sticky options.  See @ref{Invoking CVS} for
more information on the @code{status} command.

@item -l
Local; run only in current working directory.

@item -n
Do not run any checkout program (as specified
with the @samp{-o} option in the modules file;
@pxref{modules}).

@item -P
Prune empty directories.  See @ref{Moving directories}.

@item -p
Pipe files to the standard output.

@item -R
Checkout directories recursively.  This option is on by default.

@item -r @var{tag}
Use revision @var{tag}.  This option is sticky, and implies @samp{-P}.
See @ref{Sticky tags}, for more information on sticky tags/dates.
@end table

In addition to those, you can use these special command
options with @code{checkout}:

@table @code
@item -A
Reset any sticky tags, dates, or @samp{-k} options.
Does not reset sticky @samp{-k} options on modified files.
See @ref{Sticky tags} for more information on sticky tags/dates.

@item -c
Copy the module file, sorted, to the standard output,
instead of creating or modifying any files or
directories in your working directory.

@item -d @var{dir}
Create a directory called @var{dir} for the working
files, instead of using the module name.  In general,
using this flag is equivalent to using @samp{mkdir
@var{dir}; cd @var{dir}} followed by the checkout
command without the @samp{-d} flag.

There is an important exception, however.  It is very
convenient when checking out a single item to have the
output appear in a directory that doesn't contain empty
intermediate directories.  In this case @emph{only},
@sc{cvs} tries to ``shorten'' pathnames to avoid those empty
directories.

For example, given a module @samp{foo} that contains
the file @samp{bar.c}, the command @samp{cvs co -d dir
foo} will create directory @samp{dir} and place
@samp{bar.c} inside.  Similarly, given a module
@samp{bar} which has subdirectory @samp{baz} wherein
there is a file @samp{quux.c}, the command @samp{cvs co
-d dir bar/baz} will create directory @samp{dir} and
place @samp{quux.c} inside.

Using the @samp{-N} flag will defeat this behavior.
Given the same module definitions above, @samp{cvs co
-N -d dir foo} will create directories @samp{dir/foo}
and place @samp{bar.c} inside, while @samp{cvs co -N -d
dir bar/baz} will create directories @samp{dir/bar/baz}
and place @samp{quux.c} inside.

@item -j @var{tag}
With two @samp{-j} options, merge changes from the
revision specified with the first @samp{-j} option to
the revision specified with the second @samp{j} option,
into the working directory.

With one @samp{-j} option, merge changes from the
ancestor revision to the revision specified with the
@samp{-j} option, into the working directory.  The
ancestor revision is the common ancestor of the
revision which the working directory is based on, and
the revision specified in the @samp{-j} option.

In addition, each -j option can contain an optional
date specification which, when used with branches, can
limit the chosen revision to one within a specific
date.  An optional date is specified by adding a colon
(:) to the tag:
@samp{-j@var{Symbolic_Tag}:@var{Date_Specifier}}.

See @ref{Branching and merging}.

@item -N
Only useful together with @samp{-d @var{dir}}.  With
this option, @sc{cvs} will not ``shorten'' module paths
in your working directory when you check out a single
module.  See the @samp{-d} flag for examples and a
discussion.

@item -s
Like @samp{-c}, but include the status of all modules,
and sort it by the status string.  See @ref{modules}, for
info about the @samp{-s} option that is used inside the
modules file to set the module status.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node checkout examples
@appendixsubsec checkout examples

Get a copy of the module @samp{tc}:

@example
$ cvs checkout tc
@end example

Get a copy of the module @samp{tc} as it looked one day
ago:

@example
$ cvs checkout -D yesterday tc
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node commit
@appendixsec commit---Check files into the repository
@cindex commit (subcommand)

@itemize @bullet
@item
Synopsis: commit [-lRf] [-m 'log_message' |
-F file] [-r revision] [files@dots{}]
@item
Requires: working directory, repository.
@item
Changes: repository.
@item
Synonym: ci
@end itemize

Use @code{commit} when you want to incorporate changes
from your working source files into the source
repository.

If you don't specify particular files to commit, all of
the files in your working current directory are
examined.  @code{commit} is careful to change in the
repository only those files that you have really
changed.  By default (or if you explicitly specify the
@samp{-R} option), files in subdirectories are also
examined and committed if they have changed; you can
use the @samp{-l} option to limit @code{commit} to the
current directory only.

@code{commit} verifies that the selected files are up
to date with the current revisions in the source
repository; it will notify you, and exit without
committing, if any of the specified files must be made
current first with @code{update} (@pxref{update}).
@code{commit} does not call the @code{update} command
for you, but rather leaves that for you to do when the
time is right.

When all is well, an editor is invoked to allow you to
enter a log message that will be written to one or more
logging programs (@pxref{modules}, and @pxref{loginfo})
and placed in the @sc{rcs} file inside the
repository.  This log message can be retrieved with the
@code{log} command; @xref{log}.  You can specify the
log message on the command line with the @samp{-m
@var{message}} option, and thus avoid the editor invocation,
or use the @samp{-F @var{file}} option to specify
that the argument file contains the log message.

@menu
* commit options::              commit options
* commit examples::             commit examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node commit options
@appendixsubsec commit options

These standard options are supported by @code{commit}
(@pxref{Common options} for a complete description of
them):

@table @code
@item -l
Local; run only in current working directory.

@item -R
Commit directories recursively.  This is on by default.

@item -r @var{revision}
Commit to @var{revision}.  @var{revision} must be
either a branch, or a revision on the main trunk that
is higher than any existing revision number
(@pxref{Assigning revisions}).  You
cannot commit to a specific revision on a branch.
@c FIXME: Need xref for branch case.
@end table

@code{commit} also supports these options:

@table @code
@item -F @var{file}
Read the log message from @var{file}, instead
of invoking an editor.

@item -f
Note that this is not the standard behavior of
the @samp{-f} option as defined in @ref{Common options}.

Force @sc{cvs} to commit a new revision even if you haven't
made any changes to the file.  If the current revision
of @var{file} is 1.7, then the following two commands
are equivalent:

@example
$ cvs commit -f @var{file}
$ cvs commit -r 1.8 @var{file}
@end example

@c This is odd, but it's how CVS has worked for some
@c time.
The @samp{-f} option disables recursion (i.e., it
implies @samp{-l}).  To force @sc{cvs} to commit a new
revision for all files in all subdirectories, you must
use @samp{-f -R}.

@item -m @var{message}
Use @var{message} as the log message, instead of
invoking an editor.
@end table

@need 2000
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node commit examples
@appendixsubsec commit examples

@c FIXME: this material wants to be somewhere
@c in "Branching and merging".

@appendixsubsubsec Committing to a branch

You can commit to a branch revision (one that has an
even number of dots) with the @samp{-r} option.  To
create a branch revision, use the @samp{-b} option
of the @code{rtag} or @code{tag} commands
(@pxref{Branching and merging}).  Then, either @code{checkout} or
@code{update} can be used to base your sources on the
newly created branch.  From that point on, all
@code{commit} changes made within these working sources
will be automatically added to a branch revision,
thereby not disturbing main-line development in any
way.  For example, if you had to create a patch to the
1.2 version of the product, even though the 2.0 version
is already under development, you might do:

@example
$ cvs rtag -b -r FCS1_2 FCS1_2_Patch product_module
$ cvs checkout -r FCS1_2_Patch product_module
$ cd product_module
[[ hack away ]]
$ cvs commit
@end example

@noindent
This works automatically since the @samp{-r} option is
sticky.

@appendixsubsubsec Creating the branch after editing

Say you have been working on some extremely
experimental software, based on whatever revision you
happened to checkout last week.  If others in your
group would like to work on this software with you, but
without disturbing main-line development, you could
commit your change to a new branch.  Others can then
checkout your experimental stuff and utilize the full
benefit of @sc{cvs} conflict resolution.  The scenario might
look like:

@c FIXME: Should we be recommending tagging the branchpoint?
@example
[[ hacked sources are present ]]
$ cvs tag -b EXPR1
$ cvs update -r EXPR1
$ cvs commit
@end example

The @code{update} command will make the @samp{-r
EXPR1} option sticky on all files.  Note that your
changes to the files will never be removed by the
@code{update} command.  The @code{commit} will
automatically commit to the correct branch, because the
@samp{-r} is sticky.  You could also do like this:

@c FIXME: Should we be recommending tagging the branchpoint?
@example
[[ hacked sources are present ]]
$ cvs tag -b EXPR1
$ cvs commit -r EXPR1
@end example

@noindent
but then, only those files that were changed by you
will have the @samp{-r EXPR1} sticky flag.  If you hack
away, and commit without specifying the @samp{-r EXPR1}
flag, some files may accidentally end up on the main
trunk.

To work with you on the experimental change, others
would simply do

@example
$ cvs checkout -r EXPR1 whatever_module
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node diff
@appendixsec diff---Show differences between revisions
@cindex diff (subcommand)

@itemize @bullet
@item
Synopsis: diff [-lR] [-k kflag] [format_options] [[-r rev1 | -D date1] [-r rev2 |  -D date2]] [files@dots{}]
@item
Requires: working directory, repository.
@item
Changes: nothing.
@end itemize

The @code{diff} command is used to compare different
revisions of files.  The default action is to compare
your working files with the revisions they were based
on, and report any differences that are found.

If any file names are given, only those files are
compared.  If any directories are given, all files
under them will be compared.

The exit status for diff is different than for other
@sc{cvs} commands; for details @xref{Exit status}.

@menu
* diff options::                diff options
* diff examples::               diff examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node diff options
@appendixsubsec diff options

These standard options are supported by @code{diff}
(@pxref{Common options} for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.
See @samp{-r} for how this affects the comparison.

@item -k @var{kflag}
Process keywords according to @var{kflag}.  See
@ref{Keyword substitution}.

@item -l
Local; run only in current working directory.

@item -R
Examine directories recursively.  This option is on by
default.

@item -r @var{tag}
Compare with revision @var{tag}.  Zero, one or two
@samp{-r} options can be present.  With no @samp{-r}
option, the working file will be compared with the
revision it was based on.  With one @samp{-r}, that
revision will be compared to your current working file.
With two @samp{-r} options those two revisions will be
compared (and your working file will not affect the
outcome in any way).
@c We should be a lot more explicit, with examples,
@c about the difference between "cvs diff" and "cvs
@c diff -r HEAD".  This often confuses new users.

One or both @samp{-r} options can be replaced by a
@samp{-D @var{date}} option, described above.
@end table

@c Conceptually, this is a disaster.  There are 3
@c zillion diff formats that we support via the diff
@c library.  It is not obvious to me that we should
@c document them all.  Maybe just the most common ones
@c like -c and -u, and think about phasing out the
@c obscure ones.
@c FIXCVS: also should be a way to specify an external
@c diff program (which can be different for different
@c file types) and pass through
@c arbitrary options, so that the user can do
@c "--pass=-Z --pass=foo" or something even if CVS
@c doesn't know about the "-Z foo" option to diff.
@c This would fit nicely with deprecating/eliminating
@c the obscure options of the diff library, because it
@c would let people specify an external GNU diff if
@c they are into that sort of thing.
The following options specify the format of the
output.  They have the same meaning as in GNU diff.
Most options have two equivalent names, one of which is a single letter
preceded by @samp{-}, and the other of which is a long name preceded by
@samp{--}.

@table @samp
@item -@var{lines}
Show @var{lines} (an integer) lines of context.  This option does not
specify an output format by itself; it has no effect unless it is
combined with @samp{-c} or @samp{-u}.  This option is obsolete.  For proper
operation, @code{patch} typically needs at least two lines of context.

@item -a
Treat all files as text and compare them line-by-line, even if they
do not seem to be text.

@item -b
Ignore trailing white space and consider all other sequences of one or
more white space characters to be equivalent.

@item -B
Ignore changes that just insert or delete blank lines.

@item --binary
Read and write data in binary mode.

@item --brief
Report only whether the files differ, not the details of the
differences.

@item -c
Use the context output format.

@item -C @var{lines}
@itemx --context@r{[}=@var{lines}@r{]}
Use the context output format, showing @var{lines} (an integer) lines of
context, or three if @var{lines} is not given.
For proper operation, @code{patch} typically needs at least two lines of
context.

@item --changed-group-format=@var{format}
Use @var{format} to output a line group containing differing lines from
both files in if-then-else format.  See @ref{Line group formats}.

@item -d
Change the algorithm to perhaps find a smaller set of changes.  This makes
@code{diff} slower (sometimes much slower).

@item -e
@itemx --ed
Make output that is a valid @code{ed} script.

@item --expand-tabs
Expand tabs to spaces in the output, to preserve the alignment of tabs
in the input files.

@item -f
Make output that looks vaguely like an @code{ed} script but has changes
in the order they appear in the file.

@item -F @var{regexp}
In context and unified format, for each hunk of differences, show some
of the last preceding line that matches @var{regexp}.

@item --forward-ed
Make output that looks vaguely like an @code{ed} script but has changes
in the order they appear in the file.

@item -H
Use heuristics to speed handling of large files that have numerous
scattered small changes.

@item --horizon-lines=@var{lines}
Do not discard the last @var{lines} lines of the common prefix
and the first @var{lines} lines of the common suffix.

@item -i
Ignore changes in case; consider upper- and lower-case letters
equivalent.

@item -I @var{regexp}
Ignore changes that just insert or delete lines that match @var{regexp}.

@item --ifdef=@var{name}
Make merged if-then-else output using @var{name}.

@item --ignore-all-space
Ignore white space when comparing lines.

@item --ignore-blank-lines
Ignore changes that just insert or delete blank lines.

@item --ignore-case
Ignore changes in case; consider upper- and lower-case to be the same.

@item --ignore-matching-lines=@var{regexp}
Ignore changes that just insert or delete lines that match @var{regexp}.

@item --ignore-space-change
Ignore trailing white space and consider all other sequences of one or
more white space characters to be equivalent.

@item --initial-tab
Output a tab rather than a space before the text of a line in normal or
context format.  This causes the alignment of tabs in the line to look
normal.

@item -L @var{label}
Use @var{label} instead of the file name in the context format
and unified format headers.

@item --label=@var{label}
Use @var{label} instead of the file name in the context format
and unified format headers.

@item --left-column
Print only the left column of two common lines in side by side format.

@item --line-format=@var{format}
Use @var{format} to output all input lines in if-then-else format.
See @ref{Line formats}.

@item --minimal
Change the algorithm to perhaps find a smaller set of changes.  This
makes @code{diff} slower (sometimes much slower).

@item -n
Output RCS-format diffs; like @samp{-f} except that each command
specifies the number of lines affected.

@item -N
@itemx --new-file
In directory comparison, if a file is found in only one directory,
treat it as present but empty in the other directory.

@item --new-group-format=@var{format}
Use @var{format} to output a group of lines taken from just the second
file in if-then-else format.  See @ref{Line group formats}.

@item --new-line-format=@var{format}
Use @var{format} to output a line taken from just the second file in
if-then-else format.  See @ref{Line formats}.

@item --old-group-format=@var{format}
Use @var{format} to output a group of lines taken from just the first
file in if-then-else format.  See @ref{Line group formats}.

@item --old-line-format=@var{format}
Use @var{format} to output a line taken from just the first file in
if-then-else format.  See @ref{Line formats}.

@item -p
Show which C function each change is in.

@item --rcs
Output RCS-format diffs; like @samp{-f} except that each command
specifies the number of lines affected.

@item --report-identical-files
@itemx -s
Report when two files are the same.

@item --show-c-function
Show which C function each change is in.

@item --show-function-line=@var{regexp}
In context and unified format, for each hunk of differences, show some
of the last preceding line that matches @var{regexp}.

@item --side-by-side
Use the side by side output format.

@item --speed-large-files
Use heuristics to speed handling of large files that have numerous
scattered small changes.

@item --suppress-common-lines
Do not print common lines in side by side format.

@item -t
Expand tabs to spaces in the output, to preserve the alignment of tabs
in the input files.

@item -T
Output a tab rather than a space before the text of a line in normal or
context format.  This causes the alignment of tabs in the line to look
normal.

@item --text
Treat all files as text and compare them line-by-line, even if they
do not appear to be text.

@item -u
Use the unified output format.

@item --unchanged-group-format=@var{format}
Use @var{format} to output a group of common lines taken from both files
in if-then-else format.  @xref{Line group formats}.

@item --unchanged-line-format=@var{format}
Use @var{format} to output a line common to both files in if-then-else
format.  @xref{Line formats}.

@item -U @var{lines}
@itemx --unified@r{[}=@var{lines}@r{]}
Use the unified output format, showing @var{lines} (an integer) lines of
context, or three if @var{lines} is not given.
For proper operation, @code{patch} typically needs at least two lines of
context.

@item -w
Ignore white space when comparing lines.

@item -W @var{columns}
@itemx --width=@var{columns}
Use an output width of @var{columns} in side by side format.

@item -y
Use the side by side output format.
@end table

@menu
* Line group formats::          Line group formats
* Line formats::                Line formats
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node Line group formats
@appendixsubsubsec Line group formats

Line group formats let you specify formats suitable for many
applications that allow if-then-else input, including programming
languages and text formatting languages.  A line group format specifies
the output format for a contiguous group of similar lines.

For example, the following command compares the TeX file @file{myfile}
with the original version from the repository,
and outputs a merged file in which old regions are
surrounded by @samp{\begin@{em@}}-@samp{\end@{em@}} lines, and new
regions are surrounded by @samp{\begin@{bf@}}-@samp{\end@{bf@}} lines.

@example
cvs diff \
   --old-group-format='\begin@{em@}
%<\end@{em@}
' \
   --new-group-format='\begin@{bf@}
%>\end@{bf@}
' \
   myfile
@end example

The following command is equivalent to the above example, but it is a
little more verbose, because it spells out the default line group formats.

@example
cvs diff \
   --old-group-format='\begin@{em@}
%<\end@{em@}
' \
   --new-group-format='\begin@{bf@}
%>\end@{bf@}
' \
   --unchanged-group-format='%=' \
   --changed-group-format='\begin@{em@}
%<\end@{em@}
\begin@{bf@}
%>\end@{bf@}
' \
   myfile
@end example

Here is a more advanced example, which outputs a diff listing with
headers containing line numbers in a ``plain English'' style.

@example
cvs diff \
   --unchanged-group-format='' \
   --old-group-format='-------- %dn line%(n=1?:s) deleted at %df:
%<' \
   --new-group-format='-------- %dN line%(N=1?:s) added after %de:
%>' \
   --changed-group-format='-------- %dn line%(n=1?:s) changed at %df:
%<-------- to:
%>' \
   myfile
@end example

To specify a line group format, use one of the options
listed below.  You can specify up to four line group formats, one for
each kind of line group.  You should quote @var{format}, because it
typically contains shell metacharacters.

@table @samp
@item --old-group-format=@var{format}
These line groups are hunks containing only lines from the first file.
The default old group format is the same as the changed group format if
it is specified; otherwise it is a format that outputs the line group as-is.

@item --new-group-format=@var{format}
These line groups are hunks containing only lines from the second
file.  The default new group format is same as the changed group
format if it is specified; otherwise it is a format that outputs the
line group as-is.

@item --changed-group-format=@var{format}
These line groups are hunks containing lines from both files.  The
default changed group format is the concatenation of the old and new
group formats.

@item --unchanged-group-format=@var{format}
These line groups contain lines common to both files.  The default
unchanged group format is a format that outputs the line group as-is.
@end table

In a line group format, ordinary characters represent themselves;
conversion specifications start with @samp{%} and have one of the
following forms.

@table @samp
@item %<
stands for the lines from the first file, including the trailing newline.
Each line is formatted according to the old line format (@pxref{Line formats}).

@item %>
stands for the lines from the second file, including the trailing newline.
Each line is formatted according to the new line format.

@item %=
stands for the lines common to both files, including the trailing newline.
Each line is formatted according to the unchanged line format.

@item %%
stands for @samp{%}.

@item %c'@var{C}'
where @var{C} is a single character, stands for @var{C}.
@var{C} may not be a backslash or an apostrophe.
For example, @samp{%c':'} stands for a colon, even inside
the then-part of an if-then-else format, which a colon would
normally terminate.

@item %c'\@var{O}'
where @var{O} is a string of 1, 2, or 3 octal digits,
stands for the character with octal code @var{O}.
For example, @samp{%c'\0'} stands for a null character.

@item @var{F}@var{n}
where @var{F} is a @code{printf} conversion specification and @var{n} is one
of the following letters, stands for @var{n}'s value formatted with @var{F}.

@table @samp
@item e
The line number of the line just before the group in the old file.

@item f
The line number of the first line in the group in the old file;
equals @var{e} + 1.

@item l
The line number of the last line in the group in the old file.

@item m
The line number of the line just after the group in the old file;
equals @var{l} + 1.

@item n
The number of lines in the group in the old file; equals @var{l} - @var{f} + 1.

@item E, F, L, M, N
Likewise, for lines in the new file.

@end table

The @code{printf} conversion specification can be @samp{%d},
@samp{%o}, @samp{%x}, or @samp{%X}, specifying decimal, octal,
lower case hexadecimal, or upper case hexadecimal output
respectively.  After the @samp{%} the following options can appear in
sequence: a @samp{-} specifying left-justification; an integer
specifying the minimum field width; and a period followed by an
optional integer specifying the minimum number of digits.
For example, @samp{%5dN} prints the number of new lines in the group
in a field of width 5 characters, using the @code{printf} format @code{"%5d"}.

@item (@var{A}=@var{B}?@var{T}:@var{E})
If @var{A} equals @var{B} then @var{T} else @var{E}.
@var{A} and @var{B} are each either a decimal constant
or a single letter interpreted as above.
This format spec is equivalent to @var{T} if
@var{A}'s value equals @var{B}'s; otherwise it is equivalent to @var{E}.

For example, @samp{%(N=0?no:%dN) line%(N=1?:s)} is equivalent to
@samp{no lines} if @var{N} (the number of lines in the group in the
new file) is 0, to @samp{1 line} if @var{N} is 1, and to @samp{%dN lines}
otherwise.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node Line formats
@appendixsubsubsec Line formats

Line formats control how each line taken from an input file is
output as part of a line group in if-then-else format.

For example, the following command outputs text with a one-column
change indicator to the left of the text.  The first column of output
is @samp{-} for deleted lines, @samp{|} for added lines, and a space
for unchanged lines.  The formats contain newline characters where
newlines are desired on output.

@example
cvs diff \
   --old-line-format='-%l
' \
   --new-line-format='|%l
' \
   --unchanged-line-format=' %l
' \
   myfile
@end example

To specify a line format, use one of the following options.  You should
quote @var{format}, since it often contains shell metacharacters.

@table @samp
@item --old-line-format=@var{format}
formats lines just from the first file.

@item --new-line-format=@var{format}
formats lines just from the second file.

@item --unchanged-line-format=@var{format}
formats lines common to both files.

@item --line-format=@var{format}
formats all lines; in effect, it sets all three above options simultaneously.
@end table

In a line format, ordinary characters represent themselves;
conversion specifications start with @samp{%} and have one of the
following forms.

@table @samp
@item %l
stands for the contents of the line, not counting its trailing
newline (if any).  This format ignores whether the line is incomplete.

@item %L
stands for the contents of the line, including its trailing newline
(if any).  If a line is incomplete, this format preserves its
incompleteness.

@item %%
stands for @samp{%}.

@item %c'@var{C}'
where @var{C} is a single character, stands for @var{C}.
@var{C} may not be a backslash or an apostrophe.
For example, @samp{%c':'} stands for a colon.

@item %c'\@var{O}'
where @var{O} is a string of 1, 2, or 3 octal digits,
stands for the character with octal code @var{O}.
For example, @samp{%c'\0'} stands for a null character.

@item @var{F}n
where @var{F} is a @code{printf} conversion specification,
stands for the line number formatted with @var{F}.
For example, @samp{%.5dn} prints the line number using the
@code{printf} format @code{"%.5d"}.  @xref{Line group formats}, for
more about printf conversion specifications.

@end table

The default line format is @samp{%l} followed by a newline character.

If the input contains tab characters and it is important that they line
up on output, you should ensure that @samp{%l} or @samp{%L} in a line
format is just after a tab stop (e.g.@: by preceding @samp{%l} or
@samp{%L} with a tab character), or you should use the @samp{-t} or
@samp{--expand-tabs} option.

Taken together, the line and line group formats let you specify many
different formats.  For example, the following command uses a format
similar to @code{diff}'s normal format.  You can tailor this command
to get fine control over @code{diff}'s output.

@example
cvs diff \
   --old-line-format='< %l
' \
   --new-line-format='> %l
' \
   --old-group-format='%df%(f=l?:,%dl)d%dE
%<' \
   --new-group-format='%dea%dF%(F=L?:,%dL)
%>' \
   --changed-group-format='%df%(f=l?:,%dl)c%dF%(F=L?:,%dL)
%<---
%>' \
   --unchanged-group-format='' \
   myfile
@end example

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node diff examples
@appendixsubsec diff examples

The following line produces a Unidiff (@samp{-u} flag)
between revision 1.14 and 1.19 of
@file{backend.c}.  Due to the @samp{-kk} flag no
keywords are substituted, so differences that only depend
on keyword substitution are ignored.

@example
$ cvs diff -kk -u -r 1.14 -r 1.19 backend.c
@end example

Suppose the experimental branch EXPR1 was based on a
set of files tagged RELEASE_1_0.  To see what has
happened on that branch, the following can be used:

@example
$ cvs diff -r RELEASE_1_0 -r EXPR1
@end example

A command like this can be used to produce a context
diff between two releases:

@example
$ cvs diff -c -r RELEASE_1_0 -r RELEASE_1_1 > diffs
@end example

If you are maintaining ChangeLogs, a command like the following
just before you commit your changes may help you write
the ChangeLog entry.  All local modifications that have
not yet been committed will be printed.

@example
$ cvs diff -u | less
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node export
@appendixsec export---Export sources from CVS, similar to checkout
@cindex export (subcommand)

@itemize @bullet
@item
Synopsis: export [-flNnR] [-r rev|-D date] [-k subst] [-d dir] module@dots{}
@item
Requires: repository.
@item
Changes: current directory.
@end itemize

This command is a variant of @code{checkout}; use it
when you want a copy of the source for module without
the @sc{cvs} administrative directories.  For example, you
might use @code{export} to prepare source for shipment
off-site.  This command requires that you specify a
date or tag (with @samp{-D} or @samp{-r}), so that you
can count on reproducing the source you ship to others
(and thus it always prunes empty directories).

One often would like to use @samp{-kv} with @code{cvs
export}.  This causes any keywords to be
expanded such that an import done at some other site
will not lose the keyword revision information.  But be
aware that doesn't handle an export containing binary
files correctly.  Also be aware that after having used
@samp{-kv}, one can no longer use the @code{ident}
command (which is part of the @sc{rcs} suite---see
ident(1)) which looks for keyword strings.  If
you want to be able to use @code{ident} you must not
use @samp{-kv}.

@menu
* export options::              export options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node export options
@appendixsubsec export options

These standard options are supported by @code{export}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.

@item -f
If no matching revision is found, retrieve the most
recent revision (instead of ignoring the file).

@item -l
Local; run only in current working directory.

@item -n
Do not run any checkout program.

@item -R
Export directories recursively.  This is on by default.

@item -r @var{tag}
Use revision @var{tag}.
@end table

In addition, these options (that are common to
@code{checkout} and @code{export}) are also supported:

@table @code
@item -d @var{dir}
Create a directory called @var{dir} for the working
files, instead of using the module name.
See @ref{checkout options} for complete details on how
@sc{cvs} handles this flag.

@item -k @var{subst}
Set keyword expansion mode (@pxref{Substitution modes}).

@item -N
Only useful together with @samp{-d @var{dir}}.
See @ref{checkout options} for complete details on how
@sc{cvs} handles this flag.
@end table

@ignore
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@c @node export examples
@appendixsubsec export examples

Contributed examples are gratefully accepted.
@c -- Examples here!!
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node history
@appendixsec history---Show status of files and users
@cindex history (subcommand)

@itemize @bullet
@item
Synopsis:     history [-report] [-flags] [-options args] [files@dots{}]
@item
Requires: the file @file{$CVSROOT/CVSROOT/history}
@item
Changes: nothing.
@end itemize

@sc{cvs} can keep a history file that tracks each use of the
@code{checkout}, @code{commit}, @code{rtag},
@code{update}, and @code{release} commands.  You can
use @code{history} to display this information in
various formats.

Logging must be enabled by creating the file
@file{$CVSROOT/CVSROOT/history}.

@strong{@code{history} uses @samp{-f}, @samp{-l},
@samp{-n}, and @samp{-p} in ways that conflict with the
normal use inside @sc{cvs} (@pxref{Common options}).}

@menu
* history options::             history options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node history options
@appendixsubsec history options

Several options (shown above as @samp{-report})  control  what
kind of report is generated:

@table @code
@item -c
Report on each time commit was used (i.e., each time
the repository was modified).

@item -e
Everything (all record types).  Equivalent to
specifying @samp{-x} with all record types.  Of course,
@samp{-e} will also include record types which are
added in a future version of @sc{cvs}; if you are
writing a script which can only handle certain record
types, you'll want to specify @samp{-x}.

@item -m @var{module}
Report on a particular module.  (You can meaningfully
use @samp{-m} more than once on the command line.)

@item -o
Report on checked-out modules.  This is the default report type.

@item -T
Report on all tags.

@item -x @var{type}
Extract a particular set of record types @var{type} from the @sc{cvs}
history.  The types are indicated by single letters,
which you may specify in combination.

Certain commands have a single record type:

@table @code
@item F
release
@item O
checkout
@item E
export
@item T
rtag
@end table

@noindent
One of five record types may result from an update:

@table @code
@item C
A merge was necessary but collisions were
detected (requiring manual merging).
@item G
A merge was necessary and it succeeded.
@item U
A working file was copied from the repository.
@item P
A working file was patched to match the repository.
@item W
The working copy of a file was deleted during
update (because it was gone from the repository).
@end table

@noindent
One of three record types results from commit:

@table @code
@item A
A file was added for the first time.
@item M
A file was modified.
@item R
A file was removed.
@end table
@end table

The options shown as @samp{-flags} constrain or expand
the report without requiring option arguments:

@table @code
@item -a
Show data for all users (the default is to show data
only for the user executing @code{history}).

@item -l
Show last modification only.

@item -w
Show only the records for modifications done from the
same working directory where @code{history} is
executing.
@end table

The options shown as @samp{-options @var{args}} constrain the report
based on an argument:

@table @code
@item -b @var{str}
Show data back to a record containing  the  string
@var{str}  in  either the module name, the file name, or
the repository path.

@item -D @var{date}
Show data since @var{date}.  This is slightly different
from the normal use of @samp{-D @var{date}}, which
selects the newest revision older than @var{date}.

@item -f @var{file}
Show data for a particular file
(you can specify several @samp{-f} options on the same command line).
This is equivalent to specifying the file on the command line.

@item -n @var{module}
Show data for a particular module
(you can specify several @samp{-n} options on the same command line).

@item -p @var{repository}
Show data for a particular source repository  (you
can specify several @samp{-p} options on the same command
line).

@item -r @var{rev}
Show records referring to revisions since the revision
or tag named @var{rev} appears in individual @sc{rcs}
files.  Each @sc{rcs} file is searched for the revision or
tag.

@item -t @var{tag}
Show records since tag @var{tag} was last added to the
history file.  This differs from the @samp{-r} flag
above in that it reads only the history file, not the
@sc{rcs} files, and is much faster.

@item -u @var{name}
Show records for user @var{name}.

@item -z @var{timezone}
Show times in the selected records using the specified
time zone instead of UTC.
@end table

@ignore
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@c @node history examples
@appendixsubsec history examples

Contributed examples will gratefully be accepted.
@c -- Examples here!
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node import
@appendixsec import---Import sources into CVS, using vendor branches
@cindex import (subcommand)

@c FIXME: This node is way too long for one which has subnodes.

@itemize @bullet
@item
Synopsis: import [-options] repository vendortag releasetag@dots{}
@item
Requires: Repository, source distribution directory.
@item
Changes: repository.
@end itemize

Use @code{import} to incorporate an entire source
distribution from an outside source (e.g., a source
vendor) into your source repository directory.  You can
use this command both for initial creation of a
repository, and for wholesale updates to the module
from the outside source.  See @ref{Tracking sources} for
a discussion on this subject.

The @var{repository} argument gives a directory name
(or a path to a directory) under the @sc{cvs} root directory
for repositories; if the directory did not exist,
import creates it.

When you use import for updates to source that has been
modified in your source repository (since a prior
import), it will notify you of any files that conflict
in the two branches of development; use @samp{checkout
-j} to reconcile the differences, as import instructs
you to do.

If @sc{cvs} decides a file should be ignored
(@pxref{cvsignore}), it does not import it and prints
@samp{I } followed by the filename (@pxref{import output} for a
complete description of the output).

If the file @file{$CVSROOT/CVSROOT/cvswrappers} exists,
any file whose names match the specifications in that
file will be treated as packages and the appropriate
filtering will be performed on the file/directory
before being imported.  See @ref{Wrappers}.

The outside source is saved in a first-level
branch, by default 1.1.1.  Updates are leaves of this
branch; for example, files from the first imported
collection of source will be revision 1.1.1.1, then
files from the first imported update will be revision
1.1.1.2, and so on.

At least three arguments are required.
@var{repository} is needed to identify the collection
of source.  @var{vendortag} is a tag for the entire
branch (e.g., for 1.1.1).  You must also specify at
least one @var{releasetag} to uniquely identify the files at
the leaves created each time you execute @code{import}.  The
@var{releasetag} should be new, not previously existing in the
repository file, and uniquely identify the imported release,

@c I'm not completely sure this belongs here.  But
@c we need to say it _somewhere_ reasonably obvious; it
@c is a common misconception among people first learning CVS
Note that @code{import} does @emph{not} change the
directory in which you invoke it.  In particular, it
does not set up that directory as a @sc{cvs} working
directory; if you want to work with the sources import
them first and then check them out into a different
directory (@pxref{Getting the source}).

@menu
* import options::              import options
* import output::               import output
* import examples::             import examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node import options
@appendixsubsec import options

This standard option is supported by @code{import}
(@pxref{Common options} for a complete description):

@table @code
@item -m @var{message}
Use @var{message} as log information, instead of
invoking an editor.
@end table

There are the following additional special options.

@table @code
@item -b @var{branch}
See @ref{Multiple vendor branches}.

@item -k @var{subst}
Indicate the keyword expansion mode desired.  This
setting will apply to all files created during the
import, but not to any files that previously existed in
the repository.  See @ref{Substitution modes} for a
list of valid @samp{-k} settings.

@item -I @var{name}
Specify file names that should be ignored during
import.  You can use this option repeatedly.  To avoid
ignoring any files at all (even those ignored by
default), specify `-I !'.

@var{name} can be a file name pattern of the same type
that you can specify in the @file{.cvsignore} file.
See @ref{cvsignore}.
@c -- Is this really true?

@item -W @var{spec}
Specify file names that should be filtered during
import.  You can use this option repeatedly.

@var{spec} can be a file name pattern of the same type
that you can specify in the @file{.cvswrappers}
file. @xref{Wrappers}.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node import output
@appendixsubsec import output

@code{import} keeps you informed of its progress by printing a line
for each file, preceded by one character indicating the status of the file:

@table @code
@item U @var{file}
The file already exists in the repository and has not been locally
modified; a new revision has been created (if necessary).

@item N @var{file}
The file is a new file which has been added to the repository.

@item C @var{file}
The file already exists in the repository but has been locally modified;
you will have to merge the changes.

@item I @var{file}
The file is being ignored (@pxref{cvsignore}).

@cindex Symbolic link, importing
@cindex Link, symbolic, importing
@c FIXME: also (somewhere else) probably
@c should be documenting what happens if you "cvs add"
@c a symbolic link.  Also maybe what happens if
@c you manually create symbolic links within the
@c repository (? - not sure why we'd want to suggest
@c doing that).
@item L @var{file}
The file is a symbolic link; @code{cvs import} ignores symbolic links.
People periodically suggest that this behavior should
be changed, but if there is a consensus on what it
should be changed to, it doesn't seem to be apparent.
(Various options in the @file{modules} file can be used
to recreate symbolic links on checkout, update, etc.;
@pxref{modules}.)
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node import examples
@appendixsubsec import examples

See @ref{Tracking sources}, and @ref{From files}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node log
@appendixsec log---Print out log information for files
@cindex log (subcommand)

@itemize @bullet
@item
Synopsis: log [options] [files@dots{}]
@item
Requires: repository, working directory.
@item
Changes: nothing.
@end itemize

Display log information for files.  @code{log} used to
call the @sc{rcs} utility @code{rlog}.  Although this
is no longer true in the current sources, this history
determines the format of the output and the options,
which are not quite in the style of the other @sc{cvs}
commands.

@cindex Timezone, in output
@cindex Zone, time, in output
@c Kind of a funny place to document the timezone used
@c in output from commands other than @code{log}.
@c There is also more we need to say about this,
@c including what happens in a client/server environment.
The output includes the location of the @sc{rcs} file,
the @dfn{head} revision (the latest revision on the
trunk), all symbolic names (tags) and some other
things.  For each revision, the revision number, the
author, the number of lines added/deleted and the log
message are printed.  All times are displayed in
Coordinated Universal Time (UTC).  (Other parts of
@sc{cvs} print times in the local timezone).
@c FIXCVS: need a better way to control the timezone
@c used in output.  Previous/current versions of CVS did/do
@c sometimes support -z in RCSINIT, and/or an
@c undocumented (except by reference to 'rlog') -z option
@c to cvs log, but this has not been a consistent,
@c documented feature.  Perhaps a new global option,
@c where LT means the client's timezone, which the
@c client then communicates to the server, is the
@c right solution.

@strong{@code{log} uses @samp{-R} in a way that conflicts
with the normal use inside @sc{cvs} (@pxref{Common options}).}

@menu
* log options::                 log options
* log examples::                log examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node log options
@appendixsubsec log options

By default, @code{log} prints all information that is
available.  All other options restrict the output.  Note that the revision
selection options (@code{-b}, @code{-d}, @code{-r}, @code{-s}, and @code{-w})
have no
effect, other than possibly causing a search for files in Attic directories,
when used in conjunction with the options that restrict the output to only
@code{log} header fields (@code{-h}, @code{-R}, and @code{-t})
unless the @code{-S} option is also specified.

@table @code
@item -b
Print information about the revisions on the default
branch, normally the highest branch on the trunk.

@item -d @var{dates}
Print information about revisions with a checkin
date/time in the range given by the
semicolon-separated list of dates.  The date formats
accepted are those accepted by the @samp{-D} option to
many other @sc{cvs} commands (@pxref{Common options}).
Dates can be combined into ranges as follows:

@c Should we be thinking about accepting ISO8601
@c ranges?  For example "1972-09-10/1972-09-12".
@table @code
@item @var{d1}<@var{d2}
@itemx @var{d2}>@var{d1}
Select the revisions that were deposited between
@var{d1} and @var{d2}.

@item <@var{d}
@itemx @var{d}>
Select all revisions dated @var{d} or earlier.

@item @var{d}<
@itemx >@var{d}
Select all revisions dated @var{d} or later.

@item @var{d}
Select the single, latest revision dated @var{d} or
earlier.
@end table

The @samp{>} or @samp{<} characters may be followed by
@samp{=} to indicate an inclusive range rather than an
exclusive one.

Note that the separator is a semicolon (;).

@item -h
Print only the name of the @sc{rcs} file, name
of the file in the working directory, head,
default branch, access list, locks, symbolic names, and
suffix.

@item -l
Local; run only in current working directory.  (Default
is to run recursively).

@item -N
Do not print the list of tags for this file.  This
option can be very useful when your site uses a lot of
tags, so rather than "more"'ing over 3 pages of tag
information, the log information is presented without
tags at all.

@item -n
Print the list of tags for this file. This option can
be very useful when your @file{.cvsrc} file has a
@samp{log -N} entry as a way to get a full list of all
of the tags.

@item -R
Print only the name of the @sc{rcs} file.

@c Note that using a bare revision (in addition to not
@c being explicitly documented here) is potentially
@c confusing; it shows the log message to get from the
@c previous revision to that revision.  "-r1.3 -r1.6"
@c (equivalent to "-r1.3,1.6") is even worse; it
@c prints the messages to get from 1.2 to 1.3 and 1.5
@c to 1.6.  By analogy with "cvs diff", users might
@c expect that it is more like specifying a range.
@c It is not 100% clear to me how much of this should
@c be documented (for example, multiple -r options
@c perhaps could/should be deprecated given the false
@c analogy with "cvs diff").
@c In general, this section should be rewritten to talk
@c about messages to get from revision rev1 to rev2,
@c rather than messages for revision rev2 (that is, the
@c messages are associated with a change not a static
@c revision and failing to make this distinction causes
@c much confusion).
@item -r@var{revisions}
Print information about revisions given in the
comma-separated list @var{revisions} of revisions and
ranges.  The following table explains the available
range formats:

@table @code
@item @var{rev1}:@var{rev2}
Revisions @var{rev1} to @var{rev2} (which must be on
the same branch).

@item @var{rev1}::@var{rev2}
The same, but excluding @var{rev1}.

@item :@var{rev}
@itemx ::@var{rev}
Revisions from the beginning of the branch up to
and including @var{rev}.

@item @var{rev}:
Revisions starting with @var{rev} to the end of the
branch containing @var{rev}.

@item @var{rev}::
Revisions starting just after @var{rev} to the end of the
branch containing @var{rev}.

@item @var{branch}
An argument that is a branch means all revisions on
that branch.

@item @var{branch1}:@var{branch2}
@itemx @var{branch1}::@var{branch2}
A range of branches means all revisions
on the branches in that range.

@item @var{branch}.
The latest revision in @var{branch}.
@end table

A bare @samp{-r} with no revisions means the latest
revision on the default branch, normally the trunk.
There can be no space between the @samp{-r} option and
its argument.

@item -S
Suppress the header if no revisions are selected.

@item -s @var{states}
Print information about revisions whose state
attributes match one of the states given in the
comma-separated list @var{states}.  Individual states may
be any text string, though @sc{cvs} commonly only uses two
states, @samp{Exp} and @samp{dead}.  See @ref{admin options}
for more information.

@item -t
Print the same as @samp{-h}, plus the descriptive text.

@item -w@var{logins}
Print information about revisions checked in by users
with login names appearing in the comma-separated list
@var{logins}.  If @var{logins} is omitted, the user's
login is assumed.  There can be no space between the
@samp{-w} option and its argument.
@end table

@code{log} prints the intersection of the revisions
selected with the options @samp{-d}, @samp{-s}, and
@samp{-w}, intersected with the union of the revisions
selected by @samp{-b} and @samp{-r}.

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node log examples
@appendixsubsec log examples

Contributed examples are gratefully accepted.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node rdiff
@appendixsec rdiff---'patch' format diffs between releases
@cindex rdiff (subcommand)

@itemize @bullet
@item
rdiff [-flags] [-V vn] [-r t|-D d [-r t2|-D d2]] modules@dots{}
@item
Requires: repository.
@item
Changes: nothing.
@item
Synonym: patch
@end itemize

Builds a Larry Wall format patch(1) file between two
releases, that can be fed directly into the @code{patch}
program to bring an old release up-to-date with the new
release.  (This is one of the few @sc{cvs} commands that
operates directly from the repository, and doesn't
require a prior checkout.) The diff output is sent to
the standard output device.

You can specify (using the standard @samp{-r} and
@samp{-D} options) any combination of one or two
revisions or dates.  If only one revision or date is
specified, the patch file reflects differences between
that revision or date and the current head revisions in
the @sc{rcs} file.

Note that if the software release affected is contained
in more than one directory, then it may be necessary to
specify the @samp{-p} option to the @code{patch} command when
patching the old sources, so that @code{patch} is able to find
the files that are located in other directories.

@menu
* rdiff options::               rdiff options
* rdiff examples::              rdiff examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node rdiff options
@appendixsubsec rdiff options

These standard options are supported by @code{rdiff}
(@pxref{Common options} for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.

@item -f
If no matching revision is found, retrieve the most
recent revision (instead of ignoring the file).

@item -k @var{kflag}
Process keywords according to @var{kflag}.  See
@ref{Keyword substitution}.

@item -l
Local; don't descend subdirectories.

@item -R
Examine directories recursively.  This option is on by default.

@item -r @var{tag}
Use revision @var{tag}.
@end table

In addition to the above, these options are available:

@table @code
@item -c
Use the context diff format.  This is the default format.

@item -s
Create a summary change report instead of a patch.  The
summary includes information about files that were
changed or added between the releases.  It is sent to
the standard output device.  This is useful for finding
out, for example, which files have changed between two
dates or revisions.

@item -t
A diff of the top two revisions is sent to the standard
output device.  This is most useful for seeing what the
last change to a file was.

@item -u
Use the unidiff format for the context diffs.
Remember that old versions
of the @code{patch} program can't handle the unidiff
format, so if you plan to post this patch to the net
you should probably not use @samp{-u}.

@item -V @var{vn}
Expand keywords according to the rules current in
@sc{rcs} version @var{vn} (the expansion format changed with
@sc{rcs} version 5).  Note that this option is no
longer accepted.  @sc{cvs} will always expand keywords the
way that @sc{rcs} version 5 does.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node rdiff examples
@appendixsubsec rdiff examples

Suppose you receive mail from @t{foo@@example.net} asking for an
update from release 1.2 to 1.4 of the tc compiler.  You
have no such patches on hand, but with @sc{cvs} that can
easily be fixed with a command such as this:

@example
$ cvs rdiff -c -r FOO1_2 -r FOO1_4 tc | \
> Mail -s 'The patches you asked for' foo@@example.net
@end example

Suppose you have made release 1.3, and forked a branch
called @samp{R_1_3fix} for bug fixes.  @samp{R_1_3_1}
corresponds to release 1.3.1, which was made some time
ago.  Now, you want to see how much development has been
done on the branch.  This command can be used:

@example
$ cvs patch -s -r R_1_3_1 -r R_1_3fix module-name
cvs rdiff: Diffing module-name
File ChangeLog,v changed from revision 1.52.2.5 to 1.52.2.6
File foo.c,v changed from revision 1.52.2.3 to 1.52.2.4
File bar.h,v changed from revision 1.29.2.1 to 1.2
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node release
@appendixsec release---Indicate that a Module is no longer in use
@cindex release (subcommand)

@itemize @bullet
@item
release [-d] directories@dots{}
@item
Requires: Working directory.
@item
Changes: Working directory, history log.
@end itemize

This command is meant to safely cancel the effect of
@samp{cvs checkout}.  Since @sc{cvs} doesn't lock files, it
isn't strictly necessary to use this command.  You can
always simply delete your working directory, if you
like; but you risk losing changes you may have
forgotten, and you leave no trace in the @sc{cvs} history
file (@pxref{history file}) that you've abandoned your
checkout.

Use @samp{cvs release} to avoid these problems.  This
command checks that no uncommitted changes are
present; that you are executing it from immediately
above a @sc{cvs} working directory; and that the repository
recorded for your files is the same as the repository
defined in the module database.

If all these conditions are true, @samp{cvs release}
leaves a record of its execution (attesting to your
intentionally abandoning your checkout) in the @sc{cvs}
history log.

@menu
* release options::             release options
* release output::              release output
* release examples::            release examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node release options
@appendixsubsec release options

The @code{release} command supports one command option:

@table @code
@item -d
Delete your working copy of the file if the release
succeeds.  If this flag is not given your files will
remain in your working directory.

@strong{WARNING:  The @code{release} command deletes
all directories and files recursively.  This
has the very serious side-effect that any directory
created inside checked-out sources, and not added to
the repository (using the @code{add} command;
@pxref{Adding files}) will be silently deleted---even
if it is non-empty!}
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node release output
@appendixsubsec release output

Before @code{release} releases your sources it will
print a one-line message for any file that is not
up-to-date.

@table @code
@item U @var{file}
@itemx P @var{file}
There exists a newer revision of this file in the
repository, and you have not modified your local copy
of the file (@samp{U} and @samp{P} mean the same thing).

@item A @var{file}
The file has been added to your private copy of the
sources, but has not yet been committed to the
repository.  If you delete your copy of the sources
this file will be lost.

@item R @var{file}
The file has been removed from your private copy of the
sources, but has not yet been removed from the
repository, since you have not yet committed the
removal.  See @ref{commit}.

@item M @var{file}
The file is modified in your working directory.  There
might also be a newer revision inside the repository.

@item ? @var{file}
@var{file} is in your working directory, but does not
correspond to anything in the source repository, and is
not in the list of files for @sc{cvs} to ignore (see the
description of the @samp{-I} option, and
@pxref{cvsignore}).  If you remove your working
sources, this file will be lost.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node release examples
@appendixsubsec release examples

Release the @file{tc} directory, and delete your local working copy
of the files.

@example
$ cd ..         # @r{You must stand immediately above the}
                # @r{sources when you issue @samp{cvs release}.}
$ cvs release -d tc
You have [0] altered files in this repository.
Are you sure you want to release (and delete) directory `tc': y
$
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node remove
@appendixsec remove---Remove files from active use
@cindex remove (subcommand)

@itemize @bullet
@item
Synopsis: remove [-flR] [files...]
@item
Requires: repository, working directory.
@item
Changes: working directory.
@end itemize

The @code{remove} command is used to remove unwanted
files from active use.  The user normally deletes the
files from the working directory prior to invocation
of the @code{remove} command.  Only the working
directory is updated.  Changes to the repository are
not made until the @code{commit} command is run.

The @code{remove} command does not delete files from
from the repository.  @sc{cvs} keeps all historical
data in the repository so that it is possible to
reconstruct previous states of the projects under
revision control.

To undo @sc{cvs} @code{remove} or to resurrect files
that were previously removed, @xref{add}.

@menu
* remove options::             remove options
* remove examples::            remove examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node remove options
@appendixsubsec remove options

These standard options are supported by @code{remove}
(@pxref{Common options} for a complete description of
them):

@table @code
@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Process directories recursively.  See @ref{Recursive behavior}.

@end table

In addition, these options are also supported:

@table @code
@item -f
Note that this is not the standard behavior of
the @samp{-f} option as defined in @ref{Common options}.

Delete files before removing them.

Entire directory hierarchies are easily removed
using @samp{-f}, but take note that it is not as
easy to resurrect directory hierarchies as it is
to remove them.

@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node remove examples
@appendixsubsec remove examples

@appendixsubsubsec Removing a file

@example
$ cvs remove remove.me
cvs remove: file `remove.me' still in working directory
cvs remove: 1 file exists; remove it first
$ rm -f remove.me
$ cvs remove remove.me
cvs remove: scheduling `remove.me' for removal
cvs remove: use 'cvs commit' to remove this file permanently

$ ls remove.it
remove.it
$ cvs remove -f remove.it
cvs remove: scheduling `remove.it' for removal
cvs remove: use 'cvs commit' to remove this file permanently
@end example

@appendixsubsubsec Removing entire directories
@example
$ tree -d a
a
|-- CVS
`-- b
    `-- CVS

3 directories
$ cvs remove -f a
cvs remove: Removing a
cvs remove: Removing a/b
cvs remove: scheduling `a/b/c' for removal
cvs remove: use 'cvs commit' to remove this file permanently
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node update
@appendixsec update---Bring work tree in sync with repository
@cindex update (subcommand)

@itemize @bullet
@item
update [-ACdflPpR] [-I name] [-j rev [-j rev]] [-k kflag] [-r tag|-D date] [-W spec] files@dots{}
@item
Requires: repository, working directory.
@item
Changes: working directory.
@end itemize

After you've run checkout to create your private copy
of source from the common repository, other developers
will continue changing the central source.  From time
to time, when it is convenient in your development
process, you can use the @code{update} command from
within your working directory to reconcile your work
with any revisions applied to the source repository
since your last checkout or update.

@menu
* update options::              update options
* update output::               update output
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node update options
@appendixsubsec update options

These standard options are available with @code{update}
(@pxref{Common options} for a complete description of
them):

@table @code
@item -D date
Use the most recent revision no later than @var{date}.
This option is sticky, and implies @samp{-P}.
See @ref{Sticky tags} for more information on sticky tags/dates.

@item -f
Only useful with the @samp{-D @var{date}} or @samp{-r
@var{tag}} flags.  If no matching revision is found,
retrieve the most recent revision (instead of ignoring
the file).

@item -k @var{kflag}
Process keywords according to @var{kflag}.  See
@ref{Keyword substitution}.
This option is sticky; future updates of
this file in this working directory will use the same
@var{kflag}.  The @code{status} command can be viewed
to see the sticky options.  See @ref{Invoking CVS} for
more information on the @code{status} command.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -P
Prune empty directories.  See @ref{Moving directories}.

@item -p
Pipe files to the standard output.

@item -R
Update directories recursively (default).  See @ref{Recursive
behavior}.

@item -r rev
Retrieve revision/tag @var{rev}.  This option is sticky,
and implies @samp{-P}.
See @ref{Sticky tags}, for more information on sticky tags/dates.
@end table

@need 800
These special options are also available with
@code{update}.

@table @code
@item -A
Reset any sticky tags, dates, or @samp{-k} options.
Does not reset sticky @samp{-k} options on modified files.
See @ref{Sticky tags} for more information on sticky tags/dates.

@item -C
Overwrite locally modified files with clean copies from
the repository (the modified file is saved in
@file{.#@var{file}.@var{revision}}, however).

@item -d
Create any directories that exist in the repository if
they're missing from the working directory.  Normally,
@code{update} acts only on directories and files that
were already enrolled in your working directory.

This is useful for updating directories that were
created in the repository since the initial checkout;
but it has an unfortunate side effect.  If you
deliberately avoided certain directories in the
repository when you created your working directory
(either through use of a module name or by listing
explicitly the files and directories you wanted on the
command line), then updating with @samp{-d} will create
those directories, which may not be what you want.

@item -I @var{name}
Ignore files whose names match @var{name} (in your
working directory) during the update.  You can specify
@samp{-I} more than once on the command line to specify
several files to ignore.  Use @samp{-I !} to avoid
ignoring any files at all.  See @ref{cvsignore} for other
ways to make @sc{cvs} ignore some files.

@item -W@var{spec}
Specify file names that should be filtered during
update.  You can use this option repeatedly.

@var{spec} can be a file name pattern of the same type
that you can specify in the @file{.cvswrappers}
file.  See @ref{Wrappers}.

@item -j@var{revision}
With two @samp{-j} options, merge changes from the
revision specified with the first @samp{-j} option to
the revision specified with the second @samp{j} option,
into the working directory.

With one @samp{-j} option, merge changes from the
ancestor revision to the revision specified with the
@samp{-j} option, into the working directory.  The
ancestor revision is the common ancestor of the
revision which the working directory is based on, and
the revision specified in the @samp{-j} option.

Note that using a single @samp{-j @var{tagname}} option rather than
@samp{-j @var{branchname}} to merge changes from a branch will
often not remove files which were removed on the branch.
See @ref{Merging adds and removals} for more information.

In addition, each @samp{-j} option can contain an optional
date specification which, when used with branches, can
limit the chosen revision to one within a specific
date.  An optional date is specified by adding a colon
(:) to the tag:
@samp{-j@var{Symbolic_Tag}:@var{Date_Specifier}}.

See @ref{Branching and merging}.

@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node update output
@appendixsubsec update output

@code{update} and @code{checkout} keep you informed of
their progress by printing a line for each file, preceded
by one character indicating the status of the file:

@table @code
@item U @var{file}
The file was brought up to date with respect to the
repository.  This is done for any file that exists in
the repository but not in your working directory, and for files
that you haven't changed but are not the most recent
versions available in the repository.

@item P @var{file}
Like @samp{U}, but the @sc{cvs} server sends a patch instead of an entire
file.  This accomplishes the same thing as @samp{U} using less bandwidth.

@item A @var{file}
The file has been added to your private copy of the
sources, and will be added to the source repository
when you run @code{commit} on the file.  This is a
reminder to you that the file needs to be committed.

@item R @var{file}
The file has been removed from your private copy of the
sources, and will be removed from the source repository
when you run @code{commit} on the file.  This is a
reminder to you that the file needs to be committed.

@item M @var{file}
The file is modified in  your  working  directory.

@samp{M} can indicate one of two states for a file
you're working on: either there were no modifications
to the same file in the repository, so that your file
remains as you last saw it; or there were modifications
in the repository as well as in your copy, but they
were merged successfully, without conflict, in your
working directory.

@sc{cvs} will print some messages if it merges your work,
and a backup copy of your working file (as it looked
before you ran @code{update}) will be made.  The exact
name of that file is printed while @code{update} runs.

@item C @var{file}
@cindex .# files
@cindex __ files (VMS)
A conflict was detected while trying to merge your
changes to @var{file} with changes from the source
repository.  @var{file} (the copy in your working
directory) is now the result of attempting to merge
the two revisions; an unmodified copy of your file
is also in your working directory, with the name
@file{.#@var{file}.@var{revision}} where @var{revision}
is the revision that your modified file started
from.  Resolve the conflict as described in
@ref{Conflicts example}.
@c "some systems" as in out-of-the-box OSes?  Not as
@c far as I know.  We need to advise sysadmins as well
@c as users how to set up this kind of purge, if that is
@c what they want.
@c We also might want to think about cleaner solutions,
@c like having CVS remove the .# file once the conflict
@c has been resolved or something like that.
(Note that some systems automatically purge
files that begin with @file{.#} if they have not been
accessed for a few days.  If you intend to keep a copy
of your original file, it is a very good idea to rename
it.)  Under @sc{vms}, the file name starts with
@file{__} rather than @file{.#}.

@item ? @var{file}
@var{file} is in your working directory, but does not
correspond to anything in the source repository, and is
not in the list of files for @sc{cvs} to ignore (see the
description of the @samp{-I} option, and
@pxref{cvsignore}).
@end table

@c ----- END MAN 1 -----
@c ---------------------------------------------------------------------
@node Invoking CVS
@appendix Quick reference to CVS commands
@cindex Command reference
@cindex Reference, commands
@cindex Invoking CVS

This appendix describes how to invoke @sc{cvs}, with
references to where each command or feature is
described in detail.  For other references run the
@code{cvs --help} command, or see @ref{Index}.

A @sc{cvs} command looks like:

@example
cvs [ @var{global_options} ] @var{command} [ @var{command_options} ] [ @var{command_args} ]
@end example

Global options:

@table @code
@item --allow-root=@var{rootdir}
Specify legal @sc{cvsroot} directory (server only) (not
in @sc{cvs} 1.9 and older).  See @ref{Password
authentication server}.

@item -a
Authenticate all communication (client only) (not in @sc{cvs}
1.9 and older).  See @ref{Global options}.

@item -b
Specify RCS location (@sc{cvs} 1.9 and older).  See
@ref{Global options}.

@item -d @var{root}
Specify the @sc{cvsroot}.  See @ref{Repository}.

@item -e @var{editor}
Edit messages with @var{editor}.  See @ref{Committing
your changes}.

@item -f
Do not read the @file{~/.cvsrc} file.  See @ref{Global
options}.

@item -H
@itemx --help
Print a help message.  See @ref{Global options}.

@item -n
Do not change any files.  See @ref{Global options}.

@item -Q
Be really quiet.  See @ref{Global options}.

@item -q
Be somewhat quiet.  See @ref{Global options}.

@item -r
Make new working files read-only.  See @ref{Global options}.

@item -s @var{variable}=@var{value}
Set a user variable.  See @ref{Variables}.

@item -T @var{tempdir}
Put temporary files in @var{tempdir}.  See @ref{Global
options}.

@item -t
Trace @sc{cvs} execution.  See @ref{Global options}.

@item -v
@item --version
Display version and copyright information for @sc{cvs}.

@item -w
Make new working files read-write.  See @ref{Global
options}.

@item -x
Encrypt all communication (client only).
See @ref{Global options}.

@item -z @var{gzip-level}
@cindex Compression
@cindex Gzip
Set the compression level (client only).
See @ref{Global options}.
@end table

Keyword expansion modes (@pxref{Substitution modes}):

@example
-kkv  $@splitrcskeyword{Id}: file1,v 1.1 1993/12/09 03:21:13 joe Exp $
-kkvl $@splitrcskeyword{Id}: file1,v 1.1 1993/12/09 03:21:13 joe Exp harry $
-kk   $@splitrcskeyword{Id}$
-kv   file1,v 1.1 1993/12/09 03:21:13 joe Exp
-ko   @i{no expansion}
-kb   @i{no expansion, file is binary}
@end example

Keywords (@pxref{Keyword list}):

@example
$@splitrcskeyword{Author}: joe $
$@splitrcskeyword{Date}: 1993/12/09 03:21:13 $
$@splitrcskeyword{Header}: /home/files/file1,v 1.1 1993/12/09 03:21:13 joe Exp harry $
$@splitrcskeyword{Id}: file1,v 1.1 1993/12/09 03:21:13 joe Exp harry $
$@splitrcskeyword{Locker}: harry $
$@splitrcskeyword{Name}: snapshot_1_14 $
$@splitrcskeyword{RCSfile}: file1,v $
$@splitrcskeyword{Revision}: 1.1 $
$@splitrcskeyword{Source}: /home/files/file1,v $
$@splitrcskeyword{State}: Exp $
$@splitrcskeyword{Log}: file1,v $
Revision 1.1  1993/12/09 03:30:17  joe
Initial revision

@end example

@c The idea behind this table is that we want each item
@c to be a sentence or two at most.  Preferably a
@c single line.
@c
@c In some cases refs to "foo options" are just to get
@c this thing written quickly, not because the "foo
@c options" node is really the best place to point.
Commands, command options, and command arguments:

@table @code
@c ------------------------------------------------------------
@item add [@var{options}] [@var{files}@dots{}]
Add a new file/directory.  See @ref{Adding files}.

@table @code
@item -k @var{kflag}
Set keyword expansion.

@item -m @var{msg}
Set file description.
@end table

@c ------------------------------------------------------------
@item admin [@var{options}] [@var{files}@dots{}]
Administration of history files in the repository.  See
@ref{admin}.
@c This list omits those options which are not
@c documented as being useful with CVS.  That might be
@c a mistake...

@table @code
@item -b[@var{rev}]
Set default branch.  See @ref{Reverting local changes}.

@item -c@var{string}
Set comment leader.

@item -k@var{subst}
Set keyword substitution.  See @ref{Keyword
substitution}.

@item -l[@var{rev}]
Lock revision @var{rev}, or latest revision.

@item -m@var{rev}:@var{msg}
Replace the log message of revision @var{rev} with
@var{msg}.

@item -o@var{range}
Delete revisions from the repository.  See
@ref{admin options}.

@item -q
Run quietly; do not print diagnostics.

@item -s@var{state}[:@var{rev}]
Set the state.  See @ref{admin options} for more information on possible
states.

@c Does not work for client/server CVS
@item -t
Set file description from standard input.

@item -t@var{file}
Set file description from @var{file}.

@item -t-@var{string}
Set file description to @var{string}.

@item -u[@var{rev}]
Unlock revision @var{rev}, or latest revision.
@end table

@c ------------------------------------------------------------
@item annotate [@var{options}] [@var{files}@dots{}]
Show last revision where each line was modified.  See
@ref{annotate}.

@table @code
@item -D @var{date}
Annotate the most recent revision no later than
@var{date}.  See @ref{Common options}.

@item -F
Force annotation of binary files.  (Without this option,
binary files are skipped with a message.)

@item -f
Use head revision if tag/date not found.  See
@ref{Common options}.

@item -l
Local; run only in current working directory.  @xref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{tag}
Annotate revision @var{tag}.  See @ref{Common options}.
@end table

@c ------------------------------------------------------------
@item checkout [@var{options}] @var{modules}@dots{}
Get a copy of the sources.  See @ref{checkout}.

@table @code
@item -A
Reset any sticky tags/date/options.  See @ref{Sticky
tags} and @ref{Keyword substitution}.

@item -c
Output the module database.  See @ref{checkout options}.

@item -D @var{date}
Check out revisions as of @var{date} (is sticky).  See
@ref{Common options}.

@item -d @var{dir}
Check out into @var{dir}.  See @ref{checkout options}.

@item -f
Use head revision if tag/date not found.  See
@ref{Common options}.

@c Probably want to use rev1/rev2 style like for diff
@c -r.  Here and in on-line help.
@item -j @var{rev}
Merge in changes.  See @ref{checkout options}.

@item -k @var{kflag}
Use @var{kflag} keyword expansion.  See
@ref{Substitution modes}.

@item -l
Local; run only in current working directory.  @xref{Recursive behavior}.

@item -N
Don't ``shorten'' module paths if -d specified.  See
@ref{checkout options}.

@item -n
Do not run module program (if any).  See @ref{checkout options}.

@item -P
Prune empty directories.  See @ref{Moving directories}.

@item -p
Check out files to standard output (avoids
stickiness).  See @ref{checkout options}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{tag}
Checkout revision @var{tag} (is sticky).  See @ref{Common options}.

@item -s
Like -c, but include module status.  See @ref{checkout options}.
@end table

@c ------------------------------------------------------------
@item commit [@var{options}] [@var{files}@dots{}]
Check changes into the repository.  See @ref{commit}.

@table @code
@item -F @var{file}
Read log message from @var{file}.  See @ref{commit options}.

@item -f
@c What is this "disables recursion"?  It is from the
@c on-line help; is it documented in this manual?
Force the file to be committed; disables recursion.
See @ref{commit options}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -m @var{msg}
Use @var{msg} as log message.  See @ref{commit options}.

@item -n
Do not run module program (if any).  See @ref{commit options}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{rev}
Commit to @var{rev}.  See @ref{commit options}.
@c FIXME: should be dragging over text from
@c commit options, especially if it can be cleaned up
@c and made concise enough.
@end table

@c ------------------------------------------------------------
@item diff [@var{options}] [@var{files}@dots{}]
Show differences between revisions.  See @ref{diff}.
In addition to the options shown below, accepts a wide
variety of options to control output style, for example
@samp{-c} for context diffs.

@table @code
@item -D @var{date1}
Diff revision for date against working file.  See
@ref{diff options}.

@item -D @var{date2}
Diff @var{rev1}/@var{date1} against @var{date2}.  See
@ref{diff options}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -N
Include diffs for added and removed files.  See
@ref{diff options}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{rev1}
Diff revision for @var{rev1} against working file.  See
@ref{diff options}.

@item -r @var{rev2}
Diff @var{rev1}/@var{date1} against @var{rev2}.  See @ref{diff options}.
@end table

@c ------------------------------------------------------------
@item edit [@var{options}] [@var{files}@dots{}]
Get ready to edit a watched file.  See @ref{Editing files}.

@table @code
@item -a @var{actions}
Specify actions for temporary watch, where
@var{actions} is @code{edit}, @code{unedit},
@code{commit}, @code{all}, or @code{none}.  See
@ref{Editing files}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.
@end table

@c ------------------------------------------------------------
@item editors [@var{options}] [@var{files}@dots{}]
See who is editing a watched file.  See @ref{Watch information}.

@table @code
@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.
@end table

@c ------------------------------------------------------------
@item export [@var{options}] @var{modules}@dots{}
Export files from @sc{cvs}.  See @ref{export}.

@table @code
@item -D @var{date}
Check out revisions as of @var{date}.  See
@ref{Common options}.

@item -d @var{dir}
Check out into @var{dir}.  See @ref{export options}.

@item -f
Use head revision if tag/date not found.  See
@ref{Common options}.

@item -k @var{kflag}
Use @var{kflag} keyword expansion.  See
@ref{Substitution modes}.

@item -l
Local; run only in current working directory.  @xref{Recursive behavior}.

@item -N
Don't ``shorten'' module paths if -d specified.  See
@ref{export options}.

@item -n
Do not run module program (if any).  See @ref{export options}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{tag}
Checkout revision @var{tag}.  See @ref{Common options}.
@end table

@c ------------------------------------------------------------
@item history [@var{options}] [@var{files}@dots{}]
Show repository access history.  See @ref{history}.

@table @code
@item -a
All users (default is self).  See @ref{history options}.

@item -b @var{str}
Back to record with @var{str} in module/file/repos
field.  See @ref{history options}.

@item -c
Report on committed (modified) files.  See @ref{history options}.

@item -D @var{date}
Since @var{date}.  See @ref{history options}.

@item -e
Report on all record types.  See @ref{history options}.

@item -l
Last modified (committed or modified report).  See @ref{history options}.

@item -m @var{module}
Report on @var{module} (repeatable).  See @ref{history options}.

@item -n @var{module}
In @var{module}.  See @ref{history options}.

@item -o
Report on checked out modules.  See @ref{history options}.

@item -p @var{repository}
In @var{repository}.  See @ref{history options}.

@item -r @var{rev}
Since revision @var{rev}.  See @ref{history options}.

@item -T
@c What the @#$@# is a TAG?  Same as a tag?  This
@c wording is also in the online-line help.
Produce report on all TAGs.  See @ref{history options}.

@item -t @var{tag}
Since tag record placed in history file (by anyone).
See @ref{history options}.

@item -u @var{user}
For user @var{user} (repeatable).  See @ref{history options}.

@item -w
Working directory must match.  See @ref{history options}.

@item -x @var{types}
Report on @var{types}, one or more of
@code{TOEFWUPCGMAR}.  See @ref{history options}.

@item -z @var{zone}
Output for time zone @var{zone}.  See @ref{history options}.
@end table

@c ------------------------------------------------------------
@item import [@var{options}] @var{repository} @var{vendor-tag} @var{release-tags}@dots{}
Import files into @sc{cvs}, using vendor branches.  See
@ref{import}.

@table @code
@item -b @var{bra}
Import to vendor branch @var{bra}.  See
@ref{Multiple vendor branches}.

@item -d
Use the file's modification time as the time of
import.  See @ref{import options}.

@item -k @var{kflag}
Set default keyword substitution mode.  See
@ref{import options}.

@item -m @var{msg}
Use @var{msg} for log message.  See
@ref{import options}.

@item -I @var{ign}
More files to ignore (! to reset).  See
@ref{import options}.

@item -W @var{spec}
More wrappers.  See @ref{import options}.
@end table

@c ------------------------------------------------------------
@item init
Create a @sc{cvs} repository if it doesn't exist.  See
@ref{Creating a repository}.

@c ------------------------------------------------------------
@item kserver
Kerberos authenticated server.
See @ref{Kerberos authenticated}.

@c ------------------------------------------------------------
@item log [@var{options}] [@var{files}@dots{}]
Print out history information for files.  See @ref{log}.

@table @code
@item -b
Only list revisions on the default branch.  See @ref{log options}.

@item -d @var{dates}
Specify dates (@var{d1}<@var{d2} for range, @var{d} for
latest before).  See @ref{log options}.

@item -h
Only print header.  See @ref{log options}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -N
Do not list tags.  See @ref{log options}.

@item -R
Only print name of RCS file.  See @ref{log options}.

@item -r@var{revs}
Only list revisions @var{revs}.  See @ref{log options}.

@item -s @var{states}
Only list revisions with specified states.  See @ref{log options}.

@item -t
Only print header and descriptive text.  See @ref{log
options}.

@item -w@var{logins}
Only list revisions checked in by specified logins.  See @ref{log options}.
@end table

@c ------------------------------------------------------------
@item login
Prompt for password for authenticating server.  See
@ref{Password authentication client}.

@c ------------------------------------------------------------
@item logout
Remove stored password for authenticating server.  See
@ref{Password authentication client}.

@c ------------------------------------------------------------
@item pserver
Password authenticated server.
See @ref{Password authentication server}.

@c ------------------------------------------------------------
@item rannotate [@var{options}] [@var{modules}@dots{}]
Show last revision where each line was modified.  See
@ref{annotate}.

@table @code
@item -D @var{date}
Annotate the most recent revision no later than
@var{date}.  See @ref{Common options}.

@item -F
Force annotation of binary files.  (Without this option,
binary files are skipped with a message.)

@item -f
Use head revision if tag/date not found.  See
@ref{Common options}.

@item -l
Local; run only in current working directory.  @xref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive behavior}.

@item -r @var{tag}
Annotate revision @var{tag}.  See @ref{Common options}.
@end table

@c ------------------------------------------------------------
@item rdiff [@var{options}] @var{modules}@dots{}
Show differences between releases.  See @ref{rdiff}.

@table @code
@item -c
Context diff output format (default).  See @ref{rdiff options}.

@item -D @var{date}
Select revisions based on @var{date}.  See @ref{Common options}.

@item -f
Use head revision if tag/date not found.  See
@ref{Common options}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{rev}
Select revisions based on @var{rev}.  See @ref{Common options}.

@item -s
Short patch - one liner per file.  See @ref{rdiff options}.

@item -t
Top two diffs - last change made to the file.  See
@ref{diff options}.

@item -u
Unidiff output format.  See @ref{rdiff options}.

@item -V @var{vers}
Use RCS Version @var{vers} for keyword expansion (obsolete).  See
@ref{rdiff options}.
@end table

@c ------------------------------------------------------------
@item release [@var{options}] @var{directory}
Indicate that a directory is no longer in use.  See
@ref{release}.

@table @code
@item -d
Delete the given directory.  See @ref{release options}.
@end table

@c ------------------------------------------------------------
@item remove [@var{options}] [@var{files}@dots{}]
Remove an entry from the repository.  See @ref{Removing files}.

@table @code
@item -f
Delete the file before removing it.  See @ref{Removing files}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.
@end table

@c ------------------------------------------------------------
@item rlog [@var{options}] [@var{files}@dots{}]
Print out history information for modules.  See @ref{log}.

@table @code
@item -b
Only list revisions on the default branch.  See @ref{log options}.

@item -d @var{dates}
Specify dates (@var{d1}<@var{d2} for range, @var{d} for
latest before).  See @ref{log options}.

@item -h
Only print header.  See @ref{log options}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -N
Do not list tags.  See @ref{log options}.

@item -R
Only print name of RCS file.  See @ref{log options}.

@item -r@var{revs}
Only list revisions @var{revs}.  See @ref{log options}.

@item -s @var{states}
Only list revisions with specified states.  See @ref{log options}.

@item -t
Only print header and descriptive text.  See @ref{log options}.

@item -w@var{logins}
Only list revisions checked in by specified logins.  See @ref{log options}.
@end table

@c ------------------------------------------------------------
@item rtag [@var{options}] @var{tag} @var{modules}@dots{}
Add a symbolic tag to a module.
See @ref{Revisions} and @ref{Branching and merging}.

@table @code
@item -a
Clear tag from removed files that would not otherwise
be tagged.  See @ref{Tagging add/remove}.

@item -b
Create a branch named @var{tag}.  See @ref{Branching and merging}.

@item -B
Used in conjunction with -F or -d, enables movement and deletion of
branch tags.  Use with extreme caution. 

@item -D @var{date}
Tag revisions as of @var{date}.  See @ref{Tagging by date/tag}.

@item -d
Delete @var{tag}.  See @ref{Modifying tags}.

@item -F
Move @var{tag} if it already exists.  See @ref{Modifying tags}.

@item -f
Force a head revision match if tag/date not found.
See @ref{Tagging by date/tag}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -n
No execution of tag program.  See @ref{Common options}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{rev}
Tag existing tag @var{rev}.  See @ref{Tagging by date/tag}.
@end table

@c ------------------------------------------------------------
@item server
Rsh server.  See @ref{Connecting via rsh}.

@c ------------------------------------------------------------
@item status [@var{options}] @var{files}@dots{}
Display status information in a working directory.  See
@ref{File status}.

@table @code
@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -v
Include tag information for file.  See @ref{Tags}.
@end table

@c ------------------------------------------------------------
@item tag [@var{options}] @var{tag} [@var{files}@dots{}]
Add a symbolic tag to checked out version of files.
See @ref{Revisions} and @ref{Branching and merging}.

@table @code
@item -b
Create a branch named @var{tag}.  See @ref{Branching and merging}.

@item -c
Check that working files are unmodified.  See
@ref{Tagging the working directory}.

@item -D @var{date}
Tag revisions as of @var{date}.  See @ref{Tagging by date/tag}.

@item -d
Delete @var{tag}.  See @ref{Modifying tags}.

@item -F
Move @var{tag} if it already exists.  See @ref{Modifying tags}.

@item -f
Force a head revision match if tag/date not found.
See @ref{Tagging by date/tag}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{rev}
Tag existing tag @var{rev}.  See @ref{Tagging by date/tag}.
@end table

@c ------------------------------------------------------------
@item unedit [@var{options}] [@var{files}@dots{}]
Undo an edit command.  See @ref{Editing files}.

@table @code
@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive behavior}.
@end table

@c ------------------------------------------------------------
@item update [@var{options}] [@var{files}@dots{}]
Bring work tree in sync with repository.  See
@ref{update}.

@table @code
@item -A
Reset any sticky tags/date/options.  See @ref{Sticky
tags} and @ref{Keyword substitution}.

@item -C
Overwrite locally modified files with clean copies from
the repository (the modified file is saved in
@file{.#@var{file}.@var{revision}}, however).

@item -D @var{date}
Check out revisions as of @var{date} (is sticky).  See
@ref{Common options}.

@item -d
Create directories.  See @ref{update options}.

@item -f
Use head revision if tag/date not found.  See
@ref{Common options}.

@item -I @var{ign}
More files to ignore (! to reset).  See
@ref{import options}.

@c Probably want to use rev1/rev2 style like for diff
@c -r.  Here and in on-line help.
@item -j @var{rev}
Merge in changes.  See @ref{update options}.

@item -k @var{kflag}
Use @var{kflag} keyword expansion.  See
@ref{Substitution modes}.

@item -l
Local; run only in current working directory.  @xref{Recursive behavior}.

@item -P
Prune empty directories.  See @ref{Moving directories}.

@item -p
Check out files to standard output (avoids
stickiness).  See @ref{update options}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.

@item -r @var{tag}
Checkout revision @var{tag} (is sticky).  See @ref{Common options}.

@item -W @var{spec}
More wrappers.  See @ref{import options}.
@end table

@c ------------------------------------------------------------
@item version
@cindex version (subcommand)

Display the version of @sc{cvs} being used.  If the repository
is remote, display both the client and server versions.

@c ------------------------------------------------------------
@item watch [on|off|add|remove] [@var{options}] [@var{files}@dots{}]

on/off: turn on/off read-only checkouts of files.  See
@ref{Setting a watch}.

add/remove: add or remove notification on actions.  See
@ref{Getting Notified}.

@table @code
@item -a @var{actions}
Specify actions for temporary watch, where
@var{actions} is @code{edit}, @code{unedit},
@code{commit}, @code{all}, or @code{none}.  See
@ref{Editing files}.

@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.
@end table

@c ------------------------------------------------------------
@item watchers [@var{options}] [@var{files}@dots{}]
See who is watching a file.  See @ref{Watch information}.

@table @code
@item -l
Local; run only in current working directory.  See @ref{Recursive behavior}.

@item -R
Operate recursively (default).  @xref{Recursive
behavior}.
@end table

@end table

@c ---------------------------------------------------------------------
@node Administrative files
@appendix Reference manual for Administrative files
@cindex Administrative files (reference)
@cindex Files, reference manual
@cindex Reference manual (files)
@cindex CVSROOT (file)

@c FIXME?  Somewhere there needs to be a more "how-to"
@c guide to writing these.  I think the triggers
@c (commitinfo, loginfo, taginfo, &c) are perhaps a
@c different case than files like modules.  One
@c particular issue that people sometimes are
@c (unnecessarily?) worried about is performance, and
@c the impact of writing in perl or sh or ____.
Inside the repository, in the directory
@file{$CVSROOT/CVSROOT}, there are a number of
supportive files for @sc{cvs}.  You can use @sc{cvs} in a limited
fashion without any of them, but if they are set up
properly they can help make life easier.  For a
discussion of how to edit them, see @ref{Intro
administrative files}.

The most important of these files is the @file{modules}
file, which defines the modules inside the repository.

@menu
* modules::                     Defining modules
* Wrappers::                    Specify binary-ness based on file name
* Trigger Scripts::		Some notes on the commit support files and
				taginfo, referenced below.
* commit files::                The commit support files (commitinfo,
                                verifymsg, editinfo, loginfo)
* taginfo::                     Verifying/Logging tags
* rcsinfo::                     Templates for the log messages
* cvsignore::                   Ignoring files via cvsignore
* checkoutlist::                Adding your own administrative files
* history file::                History information
* Variables::                   Various variables are expanded
* config::                      Miscellaneous CVS configuration
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node modules
@appendixsec The modules file
@cindex Modules (admin file)
@cindex Defining modules (reference manual)

The @file{modules} file records your definitions of
names for collections of source code.  @sc{cvs} will
use these definitions if you use @sc{cvs} to update the
modules file (use normal commands like @code{add},
@code{commit}, etc).

The @file{modules} file may contain blank lines and
comments (lines beginning with @samp{#}) as well as
module definitions.  Long lines can be continued on the
next line by specifying a backslash (@samp{\}) as the
last character on the line.

There are three basic types of modules: alias modules,
regular modules, and ampersand modules.  The difference
between them is the way that they map files in the
repository to files in the working directory.  In all
of the following examples, the top-level repository
contains a directory called @file{first-dir}, which
contains two files, @file{file1} and @file{file2}, and a
directory @file{sdir}.  @file{first-dir/sdir} contains
a file @file{sfile}.

@c FIXME: should test all the examples in this section.

@menu
* Alias modules::             The simplest kind of module
* Regular modules::
* Ampersand modules::
* Excluding directories::     Excluding directories from a module
* Module options::            Regular and ampersand modules can take options
* Module program options::    How the modules ``program options'' programs
                              are run. 
@end menu

@node Alias modules
@appendixsubsec Alias modules
@cindex Alias modules
@cindex -a, in modules file

Alias modules are the simplest kind of module:

@table @code
@item @var{mname} -a @var{aliases}@dots{}
This represents the simplest way of defining a module
@var{mname}.  The @samp{-a} flags the definition as a
simple alias: @sc{cvs} will treat any use of @var{mname} (as
a command argument) as if the list of names
@var{aliases} had been specified instead.
@var{aliases} may contain either other module names or
paths.  When you use paths in aliases, @code{checkout}
creates all intermediate directories in the working
directory, just as if the path had been specified
explicitly in the @sc{cvs} arguments.
@end table

For example, if the modules file contains:

@example
amodule -a first-dir
@end example

@noindent
then the following two commands are equivalent:

@example
$ cvs co amodule
$ cvs co first-dir
@end example

@noindent
and they each would provide output such as:

@example
cvs checkout: Updating first-dir
U first-dir/file1
U first-dir/file2
cvs checkout: Updating first-dir/sdir
U first-dir/sdir/sfile
@end example

@node Regular modules
@appendixsubsec Regular modules
@cindex Regular modules

@table @code
@item @var{mname} [ options ] @var{dir} [ @var{files}@dots{} ]
In the simplest case, this form of module definition
reduces to @samp{@var{mname} @var{dir}}.  This defines
all the files in directory @var{dir} as module mname.
@var{dir} is a relative path (from @code{$CVSROOT}) to a
directory of source in the source repository.  In this
case, on checkout, a single directory called
@var{mname} is created as a working directory; no
intermediate directory levels are used by default, even
if @var{dir} was a path involving several directory
levels.
@end table

For example, if a module is defined by:

@example
regmodule first-dir
@end example

@noindent
then regmodule will contain the files from first-dir:

@example
$ cvs co regmodule
cvs checkout: Updating regmodule
U regmodule/file1
U regmodule/file2
cvs checkout: Updating regmodule/sdir
U regmodule/sdir/sfile
$
@end example

By explicitly specifying files in the module definition
after @var{dir}, you can select particular files from
directory @var{dir}.  Here is
an example:

@example
regfiles first-dir/sdir sfile
@end example

@noindent
With this definition, getting the regfiles module
will create a single working directory
@file{regfiles} containing the file listed, which
comes from a directory deeper
in the @sc{cvs} source repository:

@example
$ cvs co regfiles
U regfiles/sfile
$
@end example

@node Ampersand modules
@appendixsubsec Ampersand modules
@cindex Ampersand modules
@cindex &, in modules file

A module definition can refer to other modules by
including @samp{&@var{module}} in its definition.
@example
@var{mname} [ options ] @var{&module}@dots{}
@end example

Then getting the module creates a subdirectory for each such
module, in the directory containing the module.  For
example, if modules contains

@example
ampermod &first-dir
@end example

@noindent
then a checkout will create an @code{ampermod} directory
which contains a directory called @code{first-dir},
which in turns contains all the directories and files
which live there.  For example, the command

@example
$ cvs co ampermod
@end example

@noindent
will create the following files:

@example
ampermod/first-dir/file1
ampermod/first-dir/file2
ampermod/first-dir/sdir/sfile
@end example

There is one quirk/bug: the messages that @sc{cvs}
prints omit the @file{ampermod}, and thus do not
correctly display the location to which it is checking
out the files:

@example
$ cvs co ampermod
cvs checkout: Updating first-dir
U first-dir/file1
U first-dir/file2
cvs checkout: Updating first-dir/sdir
U first-dir/sdir/sfile
$
@end example

Do not rely on this buggy behavior; it may get fixed in
a future release of @sc{cvs}.

@c FIXCVS: What happens if regular and & modules are
@c combined, as in "ampermodule first-dir &second-dir"?
@c When I tried it, it seemed to just ignore the
@c "first-dir".  I think perhaps it should be an error
@c (but this needs further investigation).
@c In addition to discussing what each one does, we
@c should put in a few words about why you would use one or
@c the other in various situations.

@node Excluding directories
@appendixsubsec Excluding directories
@cindex Excluding directories, in modules file
@cindex !, in modules file

An alias module may exclude particular directories from
other modules by using an exclamation mark (@samp{!})
before the name of each directory to be excluded.

For example, if the modules file contains:

@example
exmodule -a !first-dir/sdir first-dir
@end example

@noindent
then checking out the module @samp{exmodule} will check
out everything in @samp{first-dir} except any files in
the subdirectory @samp{first-dir/sdir}.
@c Note that the "!first-dir/sdir" sometimes must be listed
@c before "first-dir".  That seems like a probable bug, in which
@c case perhaps it should be fixed (to allow either
@c order) rather than documented.  See modules4 in testsuite.

@node Module options
@appendixsubsec Module options
@cindex Options, in modules file

Either regular modules or ampersand modules can contain
options, which supply additional information concerning
the module.

@table @code
@cindex -d, in modules file
@item -d @var{name}
Name the working directory something other than the
module name.
@c FIXME: Needs a bunch of examples, analogous to the
@c examples for alias, regular, and ampersand modules
@c which show where the files go without -d.

@cindex Export program
@cindex -e, in modules file
@item -e @var{prog}
Specify a program @var{prog} to run whenever files in a
module are exported.  @var{prog} runs with a single
argument, the module name.
@c FIXME: Is it run on server? client?

@cindex Checkout program
@cindex -o, in modules file
@item -o @var{prog}
Specify a program @var{prog} to run whenever files in a
module are checked out.  @var{prog} runs with a single
argument, the module name.  See @ref{Module program options} for
information on how @var{prog} is called.
@c FIXME: Is it run on server? client?

@cindex Status of a module
@cindex Module status
@cindex -s, in modules file
@item -s @var{status}
Assign a status to the module.  When the module file is
printed with @samp{cvs checkout -s} the modules are
sorted according to primarily module status, and
secondarily according to the module name.  This option
has no other meaning.  You can use this option for
several things besides status: for instance, list the
person that is responsible for this module.

@cindex Tag program
@cindex -t, in modules file
@item -t @var{prog}
Specify a program @var{prog} to run whenever files in a
module are tagged with @code{rtag}.  @var{prog} runs
with two arguments: the module name and the symbolic
tag specified to @code{rtag}.  It is not run
when @code{tag} is executed.  Generally you will find
that the @file{taginfo} file is a better solution (@pxref{taginfo}).
@c FIXME: Is it run on server? client?
@c Problems with -t include:
@c * It is run after the tag not before
@c * It doesn't get passed all the information that
@c   taginfo does ("mov", &c).
@c * It only is run for rtag, not tag.
@end table

You should also see @pxref{Module program options} about how the
``program options'' programs are run.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

@node Module program options
@appendixsubsec How the modules file ``program options'' programs are run
@cindex Modules file program options
@cindex -t, in modules file
@cindex -o, in modules file
@cindex -e, in modules file

@noindent
For checkout, rtag, and export, the program is server-based, and as such the
following applies:-

If using remote access methods (pserver, ext, etc.),
@sc{cvs} will execute this program on the server from a temporary
directory. The path is searched for this program.

If using ``local access'' (on a local or remote NFS file system, i.e.,
repository set just to a path),
the program will be executed from the newly checked-out tree, if
found there, or alternatively searched for in the path if not.

The programs are all run after the operation has effectively
completed.


@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Wrappers
@appendixsec The cvswrappers file
@cindex cvswrappers (admin file)
@cindex CVSWRAPPERS, environment variable
@cindex Wrappers

@c FIXME: need some better way of separating this out
@c by functionality.  -m is
@c one feature, and -k is a another.  And this discussion
@c should be better motivated (e.g. start with the
@c problems, then explain how the feature solves it).

Wrappers refers to a @sc{cvs} feature which lets you
control certain settings based on the name of the file
which is being operated on.  The settings are @samp{-k}
for binary files, and @samp{-m} for nonmergeable text
files.

The @samp{-m} option
specifies the merge methodology that should be used when
a non-binary file is updated.  @code{MERGE} means the usual
@sc{cvs} behavior: try to merge the files.  @code{COPY}
means that @code{cvs update} will refuse to merge
files, as it also does for files specified as binary
with @samp{-kb} (but if the file is specified as
binary, there is no need to specify @samp{-m 'COPY'}).
@sc{cvs} will provide the user with the
two versions of the files, and require the user using
mechanisms outside @sc{cvs}, to insert any necessary
changes.

@strong{WARNING:  Do not use @code{COPY} with
@sc{cvs} 1.9 or earlier - such versions of @sc{cvs} will
copy one version of your file over the other, wiping
out the previous contents.}
@c Ordinarily we don't document the behavior of old
@c versions.  But this one is so dangerous, I think we
@c must.  I almost renamed it to -m 'NOMERGE' so we
@c could say "never use -m 'COPY'".
The @samp{-m} wrapper option only affects behavior when
merging is done on update; it does not affect how files
are stored.  See @ref{Binary files}, for more on
binary files.

The basic format of the file @file{cvswrappers} is:

@c FIXME: @example is all wrong for this.  Use @deffn or
@c something more sensible.
@example
wildcard     [option value][option value]...

where option is one of
-m           update methodology      value: MERGE or COPY
-k           keyword expansion       value: expansion mode

and value is a single-quote delimited value.
@end example

@ignore
@example
*.nib    -f 'unwrap %s' -t 'wrap %s %s' -m 'COPY'
*.c      -t 'indent %s %s'
@end example
@c When does the filter need to be an absolute pathname
@c and when will something like the above work?  I
@c suspect it relates to the PATH of the server (which
@c in turn depends on all kinds of stuff, e.g. inetd
@c for pserver).  I'm not sure whether/where to discuss
@c this.
@c FIXME: What do the %s's stand for?

@noindent
The above example of a @file{cvswrappers} file
states that all files/directories that end with a @code{.nib}
should be filtered with the @file{wrap} program before
checking the file into the repository. The file should
be filtered though the @file{unwrap} program when the
file is checked out of the repository. The
@file{cvswrappers} file also states that a @code{COPY}
methodology should be used when updating the files in
the repository (that is, no merging should be performed).

@c What pitfalls arise when using indent this way?  Is
@c it a winning thing to do?  Would be nice to at least
@c hint at those issues; we want our examples to tell
@c how to solve problems, not just to say that cvs can
@c do certain things.
The last example line says that all files that end with
@code{.c} should be filtered with @file{indent}
before being checked into the repository. Unlike the previous
example, no filtering of the @code{.c} file is done when
it is checked out of the repository.
@noindent
The @code{-t} filter is called with two arguments,
the first is the name of the file/directory to filter
and the second is the pathname to where the resulting
filtered file should be placed.

@noindent
The @code{-f} filter is called with one argument,
which is the name of the file to filter from. The end
result of this filter will be a file in the users directory
that they can work on as they normally would.

Note that the @samp{-t}/@samp{-f} features do not
conveniently handle one portion of @sc{cvs}'s operation:
determining when files are modified.  @sc{cvs} will still
want a file (or directory) to exist, and it will use
its modification time to determine whether a file is
modified.  If @sc{cvs} erroneously thinks a file is
unmodified (for example, a directory is unchanged but
one of the files within it is changed), you can force
it to check in the file anyway by specifying the
@samp{-f} option to @code{cvs commit} (@pxref{commit
options}).
@c This is, of course, a serious design flaw in -t/-f.
@c Probably the whole functionality needs to be
@c redesigned (starting from requirements) to fix this.
@end ignore

@c FIXME: We don't document -W or point to where it is
@c documented.  Or .cvswrappers.
For example, the following command imports a
directory, treating files whose name ends in
@samp{.exe} as binary:

@example
cvs import -I ! -W "*.exe -k 'b'" first-dir vendortag reltag
@end example

@c Another good example, would be storing files
@c (e.g. binary files) compressed in the repository.
@c 	::::::::::::::::::
@c 	cvswrappers
@c 	::::::::::::::::::
@c 	*.t12 -m 'COPY'
@c 	*.t[0-9][0-9] -f 'gunzipcp %s' -t 'gzipcp %s %s' -m 'COPY'
@c
@c	::::::::::::::::::
@c	gunzipcp
@c	::::::::::::::::::
@c	:
@c	[ -f $1 ] || exit 1
@c	zcat $1 > /tmp/.#$1.$$
@c	mv /tmp/.#$1.$$ $1
@c
@c	::::::::::::::::::
@c	gzipcp
@c	::::::::::::::::::
@c	:
@c	DIRNAME=`echo $1 | sed -e "s|/.*/||g"`
@c	if [ ! -d $DIRNAME ] ; then
@c	      DIRNAME=`echo $1 | sed -e "s|.*/||g"`
@c	fi
@c	gzip -c  $DIRNAME  > $2
@c One catch--"cvs diff" will not invoke the wrappers
@c (probably a CVS bug, although I haven't thought it out).

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node Trigger Scripts
@appendixsec The Trigger Scripts
@cindex Info files
@cindex Trigger scripts

Several of the administrative files support triggers, or the launching external
scripts or programs at specific times before or after particular events.  The
individual files are discussed in the later sections, @ref{commit files} and
@ref{taginfo}, but some of the common elements are discussed here.

All the trigger scripts are launched in a copy of the user sandbox being
committed, on the server, in client-server mode.  In local mode, the scripts
are actually launched directly from the user sandbox directory being committed.
For most intents and purposes, the same scripts can be run in both locations
without alteration.

@menu
* syntax::			The common syntax
* Trigger Script Security::	Trigger script security
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node syntax
@appendixsubsec The common syntax
@cindex Info files (syntax)
@cindex Syntax of info files
@cindex Common syntax of info files

@c FIXME: having this so totally separate from the
@c Variables node is rather bogus.

The administrative files such as @file{commitinfo},
@file{loginfo}, @file{rcsinfo}, @file{verifymsg}, etc.,
all have a common format.  The purpose of the files are
described later on.  The common syntax is described
here.

@cindex Regular expression syntax
Each line contains the following:
@itemize @bullet
@item
@c Say anything about DEFAULT and ALL?  Right now we
@c leave that to the description of each file (and in fact
@c the practice is inconsistent which is really annoying).
A regular expression.  This is a basic regular
expression in the syntax used by GNU emacs.
@c FIXME: What we probably should be saying is "POSIX Basic
@c Regular Expression with the following extensions (`\('
@c `\|' '+' etc)"
@c rather than define it with reference to emacs.
@c The reference to emacs is not strictly speaking
@c true, as we don't support \=, \s, or \S.  Also it isn't
@c clear we should document and/or promise to continue to
@c support all the obscure emacs extensions like \<.
@c Also need to better cite (or include) full
@c documentation for the syntax.
@c Also see comment in configure.in about what happens to the
@c syntax if we pick up a system-supplied regexp matcher.

@item
A whitespace separator---one or more spaces and/or tabs.

@item
A file name or command-line template.
@end itemize

@noindent
Blank lines are ignored.  Lines that start with the
character @samp{#} are treated as comments.  Long lines
unfortunately can @emph{not} be broken in two parts in
any way.

The first regular expression that matches the current
directory name in the repository is used.  The rest of the line
is used as a file name or command-line as appropriate.

@c FIXME: need an example.  In particular, show what
@c the regular expression is matched against (one
@c ordinarily clueful person got confused about whether it
@c includes the filename--"directory name" above should be
@c unambiguous but there is nothing like an example to
@c confirm people's understanding of this sort of thing).

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node Trigger Script Security
@appendixsubsec Security and the Trigger Scripts
@cindex Info files, security
@cindex Trigger scripts, security

Security is a huge subject, and implementing a secure system is a non-trivial
task.  This section will barely touch on all the issues involved, but it is
well to note that, as with any script you will be allowing an untrusted
user to run on your server, there are measures you can take to help prevent
your trigger scripts from being abused.

For instance, since the CVS trigger scripts all run in a copy of the user's
sandbox on the server, a naively coded Perl trigger script which attempts to
use a Perl module that is not installed on the system can be hijacked by any
user with commit access who is checking in a file with the correct name.  Other
scripting languages may be vulnerable to similar hacks.

One way to make a script more secure, at least with Perl, is to use scripts
which invoke the @code{-T}, or "taint-check" switch on their @code{#!} line.
In the most basic terms, this causes Perl to avoid running code that may have
come from an external source.  Please run the @code{perldoc perlsec} command
for more on Perl security.  Again, other languages may implement other security
verification hooks which look more or less like Perl's "taint-check" mechanism.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node commit files
@appendixsec The commit support files
@cindex Committing, administrative support files

There are three kinds of trigger scripts (@pxref{Trigger Scripts}) that can be
run at various times during a commit.  They are specified in files in the
repository, as described below.  The following table summarizes the
file names and the purpose of the corresponding programs.

@table @file
@item commitinfo
The program is responsible for checking that the commit
is allowed.  If it exits with a non-zero exit status
the commit will be aborted.

@item verifymsg
The specified program is used to evaluate the log message,
and possibly verify that it contains all required
fields.  This is most useful in combination with the
@file{rcsinfo} file, which can hold a log message
template (@pxref{rcsinfo}).

@item editinfo
The specified program is used to edit the log message,
and possibly verify that it contains all required
fields.  This is most useful in combination with the
@file{rcsinfo} file, which can hold a log message
template (@pxref{rcsinfo}).  (obsolete)

@item loginfo
The specified program is called when the commit is
complete.  It receives the log message and some
additional information and can store the log message in
a file, or mail it to appropriate persons, or maybe
post it to a local newsgroup, or@dots{}  Your
imagination is the limit!
@end table

@menu
* commitinfo::                  Pre-commit checking
* verifymsg::                   How are log messages evaluated?
* editinfo::                    Specifying how log messages are created
                                (obsolete)
* loginfo::                     Where should log messages be sent?
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node commitinfo
@appendixsubsec Commitinfo
@cindex @file{commitinfo}
@cindex Commits, precommit verification of
@cindex Precommit checking

The @file{commitinfo} file defines programs to execute
whenever @samp{cvs commit} is about to execute.  These
programs are used for pre-commit checking to verify
that the modified, added and removed files are really
ready to be committed.  This could be used, for
instance, to verify that the changed files conform to
to your site's standards for coding practice.

As mentioned earlier, each line in the
@file{commitinfo} file consists of a regular expression
and a command-line template.  The template can include
a program name and any number of arguments you wish to
supply to it.  The full path to the current source
repository is appended to the template, followed by the
file names of any files involved in the commit (added,
removed, and modified files).

@cindex Exit status, of commitinfo
The first line with a regular expression matching the
directory within the repository will be used.  If the
command returns a non-zero exit status the commit will
be aborted.
@c FIXME: need example(s) of what "directory within the
@c repository" means.

@cindex DEFAULT in commitinfo
If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

@cindex ALL in commitinfo
All occurrences of the name @samp{ALL} appearing as a
regular expression are used in addition to the first
matching regular expression or the name @samp{DEFAULT}.

@cindex @file{commitinfo}, working directory
@cindex @file{commitinfo}, command environment
The command will be run in the root of the workspace
containing the new versions of any files the user would like
to modify (commit), @emph{or in a copy of the workspace on
the server (@pxref{Remote repositories})}.  If a file is
being removed, there will be no copy of the file under the
current directory.  If a file is being added, there will be
no corresponding archive file in the repository unless the
file is being resurrected.

Note that both the repository directory and the corresponding
Attic (@pxref{Attic}) directory may need to be checked to
locate the archive file corresponding to any given file being
committed.  Much of the information about the specific commit
request being made, including the destination branch, commit
message, and command line options specified, is not available
to the command.

@c FIXME: should discuss using commitinfo to control
@c who has checkin access to what (e.g. Joe can check into
@c directories a, b, and c, and Mary can check into
@c directories b, c, and d--note this case cannot be
@c conveniently handled with unix groups).  Of course,
@c adding a new set of features to CVS might be a more
@c natural way to fix this problem than telling people to
@c use commitinfo.
@c FIXME: Should make some reference, especially in
@c the context of controlling who has access, to the fact
@c that commitinfo can be circumvented.  Perhaps
@c mention SETXID (but has it been carefully examined
@c for holes?).  This fits in with the discussion of
@c general CVS security in "Password authentication
@c security" (the bit which is not pserver-specific).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node verifymsg
@appendixsubsec Verifying log messages
@cindex @file{verifymsg} (admin file)
@cindex Log message, verifying

Once you have entered a log message, you can evaluate
that message to check for specific content, such as
a bug ID.  Use the @file{verifymsg} file to
specify a program that is used to verify the log message.
This program could be a simple script that checks
that the entered message contains the required fields.

The @file{verifymsg} file is often most useful together
with the @file{rcsinfo} file, which can be used to
specify a log message template.

Each line in the @file{verifymsg} file consists of a
regular expression and a command-line template.  The
template must include a program name, and can include
any number of arguments.  The full path to the current
log message template file is appended to the template.

One thing that should be noted is that the @samp{ALL}
keyword is not supported.  If more than one matching
line is found, the first one is used.  This can be
useful for specifying a default verification script in a
directory, and then overriding it in a subdirectory.

@cindex DEFAULT in @file{verifymsg}
If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

@cindex Exit status, of @file{verifymsg}
If the verification script exits with a non-zero exit status,
the commit is aborted.

@cindex @file{verifymsg}, changing the log message
In the default configuration, CVS allows the
verification script to change the log message. This is
controlled via the RereadLogAfterVerify CVSROOT/config
option.

When @samp{RereadLogAfterVerify=always} or
@samp{RereadLogAfterVerify=stat}, the log message will
either always be reread after the verification script
is run or reread only if the log message file status
has changed.

@xref{config}, for more on CVSROOT/config options.

It is NOT a good idea for a @file{verifymsg} script to
interact directly with the user in the various
client/server methods. For the @code{pserver} method,
there is no protocol support for communicating between
@file{verifymsg} and the client on the remote end. For the
@code{ext} and @code{server} methods, it is possible
for CVS to become confused by the characters going
along the same channel as the CVS protocol
messages. See @ref{Remote repositories}, for more
information on client/server setups.  In addition, at the time
the @file{verifymsg} script runs, the CVS
server has locks in place in the repository.  If control is
returned to the user here then other users may be stuck waiting
for access to the repository.

This option can be useful if you find yourself using an
rcstemplate that needs to be modified to remove empty
elements or to fill in default values.  It can also be
useful if the rcstemplate has changed in the repository
and the CVS/Template was not updated, but is able to be
adapted to the new format by the verification script
that is run by @file{verifymsg}.

An example of an update might be to change all
occurrences of 'BugId:' to be 'DefectId:' (which can be
useful if the rcstemplate has recently been changed and
there are still checked-out user trees with cached
copies in the CVS/Template file of the older version).

Another example of an update might be to delete a line
that contains 'BugID: none' from the log message after
validation of that value as being allowed is made.

The following is a little silly example of a
@file{verifymsg} file, together with the corresponding
@file{rcsinfo} file, the log message template and an
verification  script.  We begin with the log message template.
We want to always record a bug-id number on the first
line of the log message.  The rest of log message is
free text.  The following template is found in the file
@file{/usr/cvssupport/tc.template}.

@example
BugId:
@end example

The script @file{/usr/cvssupport/bugid.verify} is used to
evaluate the log message.

@example
#!/bin/sh
#
#       bugid.verify filename
#
#  Verify that the log message contains a valid bugid
#  on the first line.
#
if sed 1q < $1 | grep '^BugId:[ ]*[0-9][0-9]*$' > /dev/null; then
    exit 0
elif sed 1q < $1 | grep '^BugId:[ ]*none$' > /dev/null; then
    # It is okay to allow commits with 'BugId: none',
    # but do not put that text into the real log message.
    grep -v '^BugId:[ ]*none$' > $1.rewrite
    mv $1.rewrite $1
    exit 0
else
    echo "No BugId found."
    exit 1
fi
@end example

The @file{verifymsg} file contains this line:

@example
^tc     /usr/cvssupport/bugid.verify
@end example

The @file{rcsinfo} file contains this line:

@example
^tc     /usr/cvssupport/tc.template
@end example

The @file{config} file contains this line:

@example
RereadLogAfterVerify=always
@end example



@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node editinfo
@appendixsubsec Editinfo
@cindex editinfo (admin file)
@cindex Editor, specifying per module
@cindex Per-module editor
@cindex Log messages, editing

@strong{The @file{editinfo} feature has been
rendered obsolete.  To set a default editor for log
messages use the @code{CVSEDITOR}, @code{EDITOR} environment variables
(@pxref{Environment variables}) or the @samp{-e} global
option (@pxref{Global options}).  See @ref{verifymsg},
for information on the use of the @file{verifymsg}
feature for evaluating log messages.}

If you want to make sure that all log messages look the
same way, you can use the @file{editinfo} file to
specify a program that is used to edit the log message.
This program could be a custom-made editor that always
enforces a certain style of the log message, or maybe a
simple shell script that calls an editor, and checks
that the entered message contains the required fields.

If no matching line is found in the @file{editinfo}
file, the editor specified in the environment variable
@code{$CVSEDITOR} is used instead.  If that variable is
not set, then the environment variable @code{$EDITOR}
is used instead.  If that variable is not
set a default will be used.  See @ref{Committing your changes}.

The @file{editinfo} file is often most useful together
with the @file{rcsinfo} file, which can be used to
specify a log message template.

Each line in the @file{editinfo} file consists of a
regular expression and a command-line template.  The
template must include a program name, and can include
any number of arguments.  The full path to the current
log message template file is appended to the template.

One thing that should be noted is that the @samp{ALL}
keyword is not supported.  If more than one matching
line is found, the first one is used.  This can be
useful for specifying a default edit script in a
module, and then overriding it in a subdirectory.

@cindex DEFAULT in editinfo
If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

If the edit script exits with a non-zero exit status,
the commit is aborted.

Note: when @sc{cvs} is accessing a remote repository,
or when the @samp{-m} or @samp{-F} options to @code{cvs
commit} are used, @file{editinfo} will not be consulted.
There is no good workaround for this; use
@file{verifymsg} instead.

@menu
* editinfo example::            Editinfo example
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node editinfo example
@appendixsubsubsec Editinfo example

The following is a little silly example of a
@file{editinfo} file, together with the corresponding
@file{rcsinfo} file, the log message template and an
editor script.  We begin with the log message template.
We want to always record a bug-id number on the first
line of the log message.  The rest of log message is
free text.  The following template is found in the file
@file{/usr/cvssupport/tc.template}.

@example
BugId:
@end example

The script @file{/usr/cvssupport/bugid.edit} is used to
edit the log message.

@example
#!/bin/sh
#
#       bugid.edit filename
#
#  Call $EDITOR on FILENAME, and verify that the
#  resulting file contains a valid bugid on the first
#  line.
if [ "x$EDITOR" = "x" ]; then EDITOR=vi; fi
if [ "x$CVSEDITOR" = "x" ]; then CVSEDITOR=$EDITOR; fi
$CVSEDITOR $1
until head -1|grep '^BugId:[ ]*[0-9][0-9]*$' < $1
do  echo -n  "No BugId found.  Edit again? ([y]/n)"
    read ans
    case $@{ans@} in
        n*) exit 1;;
    esac
    $CVSEDITOR $1
done
@end example

The @file{editinfo} file contains this line:

@example
^tc     /usr/cvssupport/bugid.edit
@end example

The @file{rcsinfo} file contains this line:

@example
^tc     /usr/cvssupport/tc.template
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node loginfo
@appendixsubsec Loginfo
@cindex loginfo (admin file)
@cindex Storing log messages
@cindex Mailing log messages
@cindex Distributing log messages
@cindex Log messages

@c "cvs commit" is not quite right.  What we
@c mean is "when the repository gets changed" which
@c also includes "cvs import" and "cvs add" on a directory.
The @file{loginfo} file is used to control where
@samp{cvs commit} log information is sent.  The first
entry on a line is a regular expression which is tested
against the directory that the change is being made to,
relative to the @code{$CVSROOT}.  If a match is found, then
the remainder of the line is a filter program that
should expect log information on its standard input.
Note that the filter program @strong{must} read @strong{all}
of the log information or @sc{cvs} may fail with a broken pipe signal.

If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

All occurrences of the name @samp{ALL} appearing as a
regular expression are used in addition to the first
matching regular expression or @samp{DEFAULT}.

The first matching regular expression is used.

@xref{commit files}, for a description of the syntax of
the @file{loginfo} file.

The user may specify a format string as
part of the filter.  The string is composed of a
@samp{%} followed by a space, or followed by a single
format character, or followed by a set of format
characters surrounded by @samp{@{} and @samp{@}} as
separators.  The format characters are:

@table @t
@item s
file name
@item V
old version number (pre-checkin)
@item v
new version number (post-checkin)
@end table

All other characters that appear in a format string
expand to an empty field (commas separating fields are
still provided).

For example, some valid format strings are @samp{%},
@samp{%s}, @samp{%@{s@}}, and @samp{%@{sVv@}}.

The output will be a space separated string of tokens enclosed in
quotation marks (@t{"}).
Any embedded dollar signs (@t{$}), backticks (@t{`}),
backslashes (@t{\}), or quotation marks will be preceded
by a backslash (this allows the shell to correctly parse it
as a single string, reguardless of the characters it contains).
For backwards compatibility, the first
token will be the repository subdirectory.  The rest of the
tokens will be comma-delimited lists of the information
requested in the format string.  For example, if
@samp{/u/src/master/yoyodyne/tc} is the repository, @samp{%@{sVv@}}
is the format string, and three files (@t{ChangeLog},
@t{Makefile}, @t{foo.c}) were modified, the output
might be:

@example
"yoyodyne/tc ChangeLog,1.1,1.2 Makefile,1.3,1.4 foo.c,1.12,1.13"
@end example

As another example, @samp{%@{@}} means that only the
name of the repository will be generated.

Note: when @sc{cvs} is accessing a remote repository,
@file{loginfo} will be run on the @emph{remote}
(i.e., server) side, not the client side (@pxref{Remote
repositories}).

@menu
* loginfo example::             Loginfo example
* Keeping a checked out copy::  Updating a tree on every checkin
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node loginfo example
@appendixsubsubsec Loginfo example

The following @file{loginfo} file, together with the
tiny shell-script below, appends all log messages
to the file @file{$CVSROOT/CVSROOT/commitlog},
and any commits to the administrative files (inside
the @file{CVSROOT} directory) are also logged in
@file{/usr/adm/cvsroot-log}.
Commits to the @file{prog1} directory are mailed to @t{ceder}.

@c FIXME: is it a CVS feature or bug that only the
@c first matching line is used?  It is documented
@c above, but is it useful?  For example, if we wanted
@c to run both "cvs-log" and "Mail" for the CVSROOT
@c directory, it is kind of awkward if
@c only the first matching line is used.
@example
ALL             /usr/local/bin/cvs-log $CVSROOT/CVSROOT/commitlog $USER
^CVSROOT        /usr/local/bin/cvs-log /usr/adm/cvsroot-log
^prog1          Mail -s %s ceder
@end example

The shell-script @file{/usr/local/bin/cvs-log} looks
like this:

@example
#!/bin/sh
(echo "------------------------------------------------------";
 echo -n $2"  ";
 date;
 echo;
 cat) >> $1
@end example

@node Keeping a checked out copy
@appendixsubsubsec Keeping a checked out copy

@c What other index entries?  It seems like
@c people might want to use a lot of different
@c words for this functionality.
@cindex Keeping a checked out copy
@cindex Checked out copy, keeping
@cindex Web pages, maintaining with CVS

It is often useful to maintain a directory tree which
contains files which correspond to the latest version
in the repository.  For example, other developers might
want to refer to the latest sources without having to
check them out, or you might be maintaining a web site
with @sc{cvs} and want every checkin to cause the files
used by the web server to be updated.
@c Can we offer more details on the web example?  Or
@c point the user at how to figure it out?  This text
@c strikes me as sufficient for someone who already has
@c some idea of what we mean but not enough for the naive
@c user/sysadmin to understand it and set it up.

The way to do this is by having loginfo invoke
@code{cvs update}.  Doing so in the naive way will
cause a problem with locks, so the @code{cvs update}
must be run in the background.
@c Should we try to describe the problem with locks?
@c It seems like a digression for someone who just
@c wants to know how to make it work.
@c Another choice which might work for a single file
@c is to use "cvs -n update -p" which doesn't take
@c out locks (I think) but I don't see many advantages
@c of that and we might as well document something which
@c works for multiple files.
Here is an example for unix (this should all be on one line):

@example
^cyclic-pages		(date; cat; (sleep 2; cd /u/www/local-docs;
 cvs -q update -d) &) >> $CVSROOT/CVSROOT/updatelog 2>&1
@end example

This will cause checkins to repository directories
starting with @code{cyclic-pages} to update the checked
out tree in @file{/u/www/local-docs}.
@c More info on some of the details?  The "sleep 2" is
@c so if we are lucky the lock will be gone by the time
@c we start and we can wait 2 seconds instead of 30.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node rcsinfo
@appendixsec Rcsinfo
@cindex rcsinfo (admin file)
@cindex Form for log message
@cindex Log message template
@cindex Template for log message

The @file{rcsinfo} file can be used to specify a form to
edit when filling out the commit log.  The
@file{rcsinfo} file has a syntax similar to the
@file{verifymsg}, @file{commitinfo} and @file{loginfo}
files.  @xref{syntax}.  Unlike the other files the second
part is @emph{not} a command-line template.  Instead,
the part after the regular expression should be a full pathname to
a file containing the log message template.

If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

All occurrences of the name @samp{ALL} appearing as a
regular expression are used in addition to the first
matching regular expression or @samp{DEFAULT}.

@c FIXME: should be offering advice, somewhere around
@c here, about where to put the template file.  The
@c verifymsg example uses /usr/cvssupport but doesn't
@c say anything about what that directory is for or
@c whether it is hardwired into CVS or who creates
@c it or anything.  In particular we should say
@c how to version control the template file.  A
@c probably better answer than the /usr/cvssupport
@c stuff is to use checkoutlist (with xref to the
@c checkoutlist doc).
@c Also I am starting to see a connection between
@c this and the Keeping a checked out copy node.
@c Probably want to say something about that.
The log message template will be used as a default log
message.  If you specify a log message with @samp{cvs
commit -m @var{message}} or @samp{cvs commit -f
@var{file}} that log message will override the
template.

@xref{verifymsg}, for an example @file{rcsinfo}
file.

When @sc{cvs} is accessing a remote repository,
the contents of @file{rcsinfo} at the time a directory
is first checked out will specify a template which does
not then change.  If you edit @file{rcsinfo} or its
templates, you may need to check out a new working
directory.
@c Would be nice to fix CVS so this isn't needed.  For
@c example, a mechanism analogous to CVS/Entries, where
@c the client keeps track of what version of the template
@c it has.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node taginfo
@appendixsec Taginfo
@cindex taginfo (admin file)
@cindex Tags, logging
@cindex Tags, verifying
The @file{taginfo} file defines programs to execute
when someone executes a @code{tag} or @code{rtag}
command.  The @file{taginfo} file has the standard form
for trigger scripts (@pxref{Trigger Scripts}),
where each line is a regular expression
followed by a command to execute (@pxref{syntax}).  The arguments passed
to the command are, in order, the @var{tagname},
@var{operation} (@code{add} for @code{tag},
@code{mov} for @code{tag -F}, and @code{del} for
@code{tag -d}), @var{repository}, and any remaining are
pairs of @var{filename} @var{revision}.  A non-zero
exit of the filter program will cause the tag to be
aborted.

Here is an example of using the @file{taginfo} file
to log @code{tag} and @code{rtag}
commands.  In the @file{taginfo} file put:

@example
ALL /usr/local/cvsroot/CVSROOT/loggit
@end example

@noindent
Where @file{/usr/local/cvsroot/CVSROOT/loggit} contains the
following script:

@example
#!/bin/sh
echo "$@@" >>/home/kingdon/cvsroot/CVSROOT/taglog
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node cvsignore
@appendixsec Ignoring files via cvsignore
@cindex cvsignore (admin file), global
@cindex Global cvsignore
@cindex Ignoring files
@c -- This chapter should maybe be moved to the
@c tutorial part of the manual?

There are certain file names that frequently occur
inside your working copy, but that you don't want to
put under @sc{cvs} control.  Examples are all the object
files that you get while you compile your sources.
Normally, when you run @samp{cvs update}, it prints a
line for each file it encounters that it doesn't know
about (@pxref{update output}).

@sc{cvs} has a list of files (or sh(1) file name patterns)
that it should ignore while running @code{update},
@code{import} and @code{release}.
@c -- Are those the only three commands affected?
This list is constructed in the following way.

@itemize @bullet
@item
The list is initialized to include certain file name
patterns: names associated with @sc{cvs}
administration, or with other common source control
systems; common names for patch files, object files,
archive files, and editor backup files; and other names
that are usually artifacts of assorted utilities.
Currently, the default list of ignored file name
patterns is:

@cindex Ignored files
@cindex Automatically ignored files
@example
    RCS     SCCS    CVS     CVS.adm
    RCSLOG  cvslog.*
    tags    TAGS
    .make.state     .nse_depinfo
    *~      #*      .#*     ,*      _$*     *$
    *.old   *.bak   *.BAK   *.orig  *.rej   .del-*
    *.a     *.olb   *.o     *.obj   *.so    *.exe
    *.Z     *.elc   *.ln
    core
@end example

@item
The per-repository list in
@file{$CVSROOT/CVSROOT/cvsignore} is appended to
the list, if that file exists.

@item
The per-user list in @file{.cvsignore} in your home
directory is appended to the list, if it exists.

@item
Any entries in the environment variable
@code{$CVSIGNORE} is appended to the list.

@item
Any @samp{-I} options given to @sc{cvs} is appended.

@item
As @sc{cvs} traverses through your directories, the contents
of any @file{.cvsignore} will be appended to the list.
The patterns found in @file{.cvsignore} are only valid
for the directory that contains them, not for
any sub-directories.
@end itemize

In any of the 5 places listed above, a single
exclamation mark (@samp{!}) clears the ignore list.
This can be used if you want to store any file which
normally is ignored by @sc{cvs}.

Specifying @samp{-I !} to @code{cvs import} will import
everything, which is generally what you want to do if
you are importing files from a pristine distribution or
any other source which is known to not contain any
extraneous files.  However, looking at the rules above
you will see there is a fly in the ointment; if the
distribution contains any @file{.cvsignore} files, then
the patterns from those files will be processed even if
@samp{-I !} is specified.  The only workaround is to
remove the @file{.cvsignore} files in order to do the
import.  Because this is awkward, in the future
@samp{-I !} might be modified to override
@file{.cvsignore} files in each directory.

Note that the syntax of the ignore files consists of a
series of lines, each of which contains a space
separated list of filenames.  This offers no clean way
to specify filenames which contain spaces, but you can
use a workaround like @file{foo?bar} to match a file
named @file{foo bar} (it also matches @file{fooxbar}
and the like).  Also note that there is currently no
way to specify comments.
@c FIXCVS?  I don't _like_ this syntax at all, but
@c changing it raises all the usual compatibility
@c issues and I'm also not sure what to change it to.

@node checkoutlist
@appendixsec The checkoutlist file
@cindex checkoutlist

It may be helpful to use @sc{cvs} to maintain your own
files in the @file{CVSROOT} directory.  For example,
suppose that you have a script @file{logcommit.pl}
which you run by including the following line in the
@file{commitinfo} administrative file:

@example
ALL   $CVSROOT/CVSROOT/logcommit.pl
@end example

To maintain @file{logcommit.pl} with @sc{cvs} you would
add the following line to the @file{checkoutlist}
administrative file:

@example
logcommit.pl
@end example

The format of @file{checkoutlist} is one line for each
file that you want to maintain using @sc{cvs}, giving
the name of the file, followed optionally by more whitespace
and any error message that should print if the file cannot be
checked out into CVSROOT after a commit:

@example
logcommit.pl	Could not update CVSROOT/logcommit.pl.
@end example

After setting up @file{checkoutlist} in this fashion,
the files listed there will function just like
@sc{cvs}'s built-in administrative files.  For example,
when checking in one of the files you should get a
message such as:

@example
cvs commit: Rebuilding administrative file database
@end example

@noindent
and the checked out copy in the @file{CVSROOT}
directory should be updated.

Note that listing @file{passwd} (@pxref{Password
authentication server}) in @file{checkoutlist} is not
recommended for security reasons.

For information about keeping a checkout out copy in a
more general context than the one provided by
@file{checkoutlist}, see @ref{Keeping a checked out
copy}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node history file
@appendixsec The history file
@cindex History file
@cindex Log information, saving

The file @file{$CVSROOT/CVSROOT/history} is used
to log information for the @code{history} command
(@pxref{history}).  This file must be created to turn
on logging.  This is done automatically if the
@code{cvs init} command is used to set up the
repository (@pxref{Creating a repository}).

The file format of the @file{history} file is
documented only in comments in the @sc{cvs} source
code, but generally programs should use the @code{cvs
history} command to access it anyway, in case the
format changes with future releases of @sc{cvs}.

@node Variables
@appendixsec Expansions in administrative files
@cindex Internal variables
@cindex Variables

Sometimes in writing an administrative file, you might
want the file to be able to know various things based
on environment @sc{cvs} is running in.  There are
several mechanisms to do that.

To find the home directory of the user running @sc{cvs}
(from the @code{HOME} environment variable), use
@samp{~} followed by @samp{/} or the end of the line.
Likewise for the home directory of @var{user}, use
@samp{~@var{user}}.  These variables are expanded on
the server machine, and don't get any reasonable
expansion if pserver (@pxref{Password authenticated})
is in use; therefore user variables (see below) may be
a better choice to customize behavior based on the user
running @sc{cvs}.
@c Based on these limitations, should we deprecate ~?
@c What is it good for?  Are people using it?

One may want to know about various pieces of
information internal to @sc{cvs}.  A @sc{cvs} internal
variable has the syntax @code{$@{@var{variable}@}},
where @var{variable} starts with a letter and consists
of alphanumeric characters and @samp{_}.  If the
character following @var{variable} is a
non-alphanumeric character other than @samp{_}, the
@samp{@{} and @samp{@}} can be omitted.  The @sc{cvs}
internal variables are:

@table @code
@item CVSROOT
@cindex CVSROOT, internal variable
This is the absolute path to the current @sc{cvs} root directory.
@xref{Repository}, for a description of the various
ways to specify this, but note that the internal
variable contains just the directory and not any
of the access method information.

@item RCSBIN
@cindex RCSBIN, internal variable
In @sc{cvs} 1.9.18 and older, this specified the
directory where @sc{cvs} was looking for @sc{rcs}
programs.  Because @sc{cvs} no longer runs @sc{rcs}
programs, specifying this internal variable is now an
error.

@item CVSEDITOR
@cindex CVSEDITOR, internal variable
@itemx EDITOR
@cindex EDITOR, internal variable
@itemx VISUAL
@cindex VISUAL, internal variable
These all expand to the same value, which is the editor
that @sc{cvs} is using.  @xref{Global options}, for how
to specify this.

@item USER
@cindex USER, internal variable
Username of the user running @sc{cvs} (on the @sc{cvs}
server machine).
When using pserver, this is the user specified in the repository
specification which need not be the same as the username the
server is running as (@pxref{Password authentication server}).
Do not confuse this with the environment variable of the same name.
@end table

If you want to pass a value to the administrative files
which the user who is running @sc{cvs} can specify,
use a user variable.
@cindex User variables
To expand a user variable, the
administrative file contains
@code{$@{=@var{variable}@}}.  To set a user variable,
specify the global option @samp{-s} to @sc{cvs}, with
argument @code{@var{variable}=@var{value}}.  It may be
particularly useful to specify this option via
@file{.cvsrc} (@pxref{~/.cvsrc}).

For example, if you want the administrative file to
refer to a test directory you might create a user
variable @code{TESTDIR}.  Then if @sc{cvs} is invoked
as

@example
cvs -s TESTDIR=/work/local/tests
@end example

@noindent
and the
administrative file contains @code{sh
$@{=TESTDIR@}/runtests}, then that string is expanded
to @code{sh /work/local/tests/runtests}.

All other strings containing @samp{$} are reserved;
there is no way to quote a @samp{$} character so that
@samp{$} represents itself.

Environment variables passed to administrative files are:

@table @code
@cindex environment variables, passed to administrative files

@item CVS_USER
@cindex CVS_USER, environment variable
The @sc{cvs}-specific username provided by the user, if it
can be provided (currently just for the pserver access
method), and to the empty string otherwise.  (@code{CVS_USER}
and @code{USER} may differ when @file{$CVSROOT/CVSROOT/passwd}
is used to map @sc{cvs} usernames to system usernames.)

@item LOGNAME
@cindex LOGNAME, environment variable
The username of the system user.

@item USER
@cindex USER, environment variable
Same as @code{LOGNAME}.
Do not confuse this with the internal variable of the same name.
@end table

@node config
@appendixsec The CVSROOT/config configuration file

@cindex config, in CVSROOT
@cindex CVSROOT/config

The administrative file @file{config} contains various
miscellaneous settings which affect the behavior of
@sc{cvs}.  The syntax is slightly different from the
other administrative files.  Variables are not
expanded.  Lines which start with @samp{#} are
considered comments.
@c FIXME: where do we define comments for the other
@c administrative files.
Other lines consist of a keyword, @samp{=}, and a
value.  Note that this syntax is very strict.
Extraneous spaces or tabs are not permitted.
@c See comments in parseinfo.c:parse_config for more
@c discussion of this strictness.

Currently defined keywords are:

@table @code
@cindex RCSBIN, in CVSROOT/config
@item RCSBIN=@var{bindir}
For @sc{cvs} 1.9.12 through 1.9.18, this setting told
@sc{cvs} to look for @sc{rcs} programs in the
@var{bindir} directory.  Current versions of @sc{cvs}
do not run @sc{rcs} programs; for compatibility this
setting is accepted, but it does nothing.

@cindex SystemAuth, in CVSROOT/config
@item SystemAuth=@var{value}
If @var{value} is @samp{yes}, then pserver should check
for users in the system's user database if not found in
@file{CVSROOT/passwd}.  If it is @samp{no}, then all
pserver users must exist in @file{CVSROOT/passwd}.
The default is @samp{yes}.  For more on pserver, see
@ref{Password authenticated}.

@ignore
@cindex PreservePermissions, in CVSROOT/config
@item PreservePermissions=@var{value}
Enable support for saving special device files,
symbolic links, file permissions and ownerships in the
repository.  The default value is @samp{no}.
@xref{Special Files}, for the full implications of using
this keyword.
@end ignore

@cindex TopLevelAdmin, in CVSROOT/config
@item TopLevelAdmin=@var{value}
Modify the @samp{checkout} command to create a
@samp{CVS} directory at the top level of the new
working directory, in addition to @samp{CVS}
directories created within checked-out directories.
The default value is @samp{no}.

This option is useful if you find yourself performing
many commands at the top level of your working
directory, rather than in one of the checked out
subdirectories.  The @file{CVS} directory created there
will mean you don't have to specify @code{CVSROOT} for
each command.  It also provides a place for the
@file{CVS/Template} file (@pxref{Working directory
storage}).

@cindex LockDir, in CVSROOT/config
@item LockDir=@var{directory}
Put @sc{cvs} lock files in @var{directory} rather than
directly in the repository.  This is useful if you want
to let users read from the repository while giving them
write access only to @var{directory}, not to the
repository.
It can also be used to put the locks on a very fast
in-memory file system to speed up locking and unlocking
the repository.
You need to create @var{directory}, but
@sc{cvs} will create subdirectories of @var{directory} as it
needs them.  For information on @sc{cvs} locks, see
@ref{Concurrency}.

@c Mention this in Compatibility section?
Before enabling the LockDir option, make sure that you
have tracked down and removed any copies of @sc{cvs} 1.9 or
older.  Such versions neither support LockDir, nor will
give an error indicating that they don't support it.
The result, if this is allowed to happen, is that some
@sc{cvs} users will put the locks one place, and others will
put them another place, and therefore the repository
could become corrupted.  @sc{cvs} 1.10 does not support
LockDir but it will print a warning if run on a
repository with LockDir enabled.

@cindex LogHistory, in CVSROOT/config
@item LogHistory=@var{value}
Control what is logged to the @file{CVSROOT/history} file (@pxref{history}).
Default of @samp{TOEFWUPCGMAR} (or simply @samp{all}) will log
all transactions.  Any subset of the default is
legal.  (For example, to only log transactions that modify the
@file{*,v} files, use @samp{LogHistory=TMAR}.)

@cindex RereadLogAfterVerify, in CVSROOT/config
@cindex @file{verifymsg}, changing the log message
@item RereadLogAfterVerify=@var{value}
Modify the @samp{commit} command such that CVS will reread the
log message after running the program specified by @file{verifymsg}.
@var{value} may be one of @samp{yes} or @samp{always}, indicating that
the log message should always be reread; @samp{no}
or @samp{never}, indicating that it should never be
reread; or @var{value} may be @samp{stat}, indicating
that the file should be checked with the file system
@samp{stat()} function to see if it has changed (see warning below)
before rereading.  The default value is @samp{always}.

@strong{The `stat' mode can cause CVS to pause for up to
one extra second per directory committed.  This can be less IO and
CPU intensive but is not recommended for use with large repositories}

@xref{verifymsg}, for more information on how verifymsg
may be used.

@cindex IgnoreUnknownConfigKeys, in CVSROOT/config
@item IgnoreUnknownConfigKeys=@var{value}
If @var{value} is @samp{yes}, then @sc{cvs} should
ignore any keywords in @file{CVSROOT/config} which it
does not recognize. This option is intended primarily
for transitions between versions of @sc{cvs} which
support more configuration options in an environment
where a read-only mirror of the current @sc{cvs} server
may be maintained by someone else who is not yet ready
to upgrade to the same version. It is recommended that
this option be used only for a short time so that
problems with the @file{CVSROOT/config} file will be
found quickly. The default is @samp{no}.
@end table

@c ---------------------------------------------------------------------
@node Environment variables
@appendix All environment variables which affect CVS
@cindex Environment variables
@cindex Reference manual for variables

This is a complete list of all environment variables
that affect @sc{cvs}.

@table @code
@cindex CVSIGNORE, environment variable
@item $CVSIGNORE
A whitespace-separated list of file name patterns that
@sc{cvs} should ignore. @xref{cvsignore}.

@cindex CVSWRAPPERS, environment variable
@item $CVSWRAPPERS
A whitespace-separated list of file name patterns that
@sc{cvs} should treat as wrappers. @xref{Wrappers}.

@cindex CVSREAD, environment variable
@cindex Read-only files, and CVSREAD
@item $CVSREAD
If this is set, @code{checkout} and @code{update} will
try hard to make the files in your working directory
read-only.  When this is not set, the default behavior
is to permit modification of your working files.

@item $CVSUMASK
Controls permissions of files in the repository.  See
@ref{File permissions}.

@item $CVSROOT
Should contain the full pathname to the root of the @sc{cvs}
source repository (where the @sc{rcs} files are
kept).  This information must be available to @sc{cvs} for
most commands to execute; if @code{$CVSROOT} is not set,
or if you wish to override it for one invocation, you
can supply it on the command line: @samp{cvs -d cvsroot
cvs_command@dots{}} Once you have checked out a working
directory, @sc{cvs} stores the appropriate root (in
the file @file{CVS/Root}), so normally you only need to
worry about this when initially checking out a working
directory.

@item $CVSEDITOR
@cindex CVSEDITOR, environment variable
@itemx $EDITOR
@cindex EDITOR, environment variable
@itemx $VISUAL
@cindex VISUAL, environment variable
Specifies the program to use for recording log messages
during commit.  @code{$CVSEDITOR} overrides
@code{$EDITOR}, which overrides @code{$VISUAL}.
See @ref{Committing your changes} for more or
@ref{Global options} for alternative ways of specifying a
log editor.

@cindex PATH, environment variable
@item $PATH
If @code{$RCSBIN} is not set, and no path is compiled
into @sc{cvs}, it will use @code{$PATH} to try to find all
programs it uses.

@cindex HOME, environment variable
@item $HOME
@cindex HOMEPATH, environment variable
@item $HOMEPATH
@cindex HOMEDRIVE, environment variable
@item $HOMEDRIVE
Used to locate the directory where the @file{.cvsrc}
file, and other such files, are searched.  On Unix, @sc{cvs}
just checks for @code{HOME}.  On Windows NT, the system will
set @code{HOMEDRIVE}, for example to @samp{d:} and @code{HOMEPATH},
for example to @file{\joe}.  On Windows 95, you'll
probably need to set @code{HOMEDRIVE} and @code{HOMEPATH} yourself.
@c We are being vague about whether HOME works on
@c Windows; see long comment in windows-NT/filesubr.c.

@cindex CVS_RSH, environment variable
@item $CVS_RSH
Specifies the external program which @sc{cvs} connects with,
when @code{:ext:} access method is specified.
@pxref{Connecting via rsh}.

@cindex CVS_SSH, environment variable
@item $CVS_SSH
Specifies the external program which @sc{cvs} connects with,
when @code{:extssh:} access method is specified.
@pxref{Connecting via rsh}.

@item $CVS_SERVER
Used in client-server mode when accessing a remote
repository using @sc{rsh}.  It specifies the name of
the program to start on the server side (and any
necessary arguments) when accessing a remote repository
using the @code{:ext:}, @code{:fork:}, or @code{:server:} access methods.
The default value for @code{:ext:} and @code{:server:} is @code{cvs};
the default value for @code{:fork:} is the name used to run the client.
@pxref{Connecting via rsh}

@item $CVS_PASSFILE
Used in client-server mode when accessing the @code{cvs
login server}.  Default value is @file{$HOME/.cvspass}.
@pxref{Password authentication client}

@item $CVS_CLIENT_PORT
Used in client-server mode to set the port to use when accessing the server
via Kerberos, GSSAPI, or @sc{cvs}'s password authentication protocol
if the port is not specified in the CVSROOT.
@pxref{Remote repositories}

@cindex CVS_RCMD_PORT, environment variable
@item $CVS_RCMD_PORT
Used in client-server mode.  If set, specifies the port
number to be used when accessing the @sc{rcmd} demon on
the server side. (Currently not used for Unix clients).

@cindex CVS_CLIENT_LOG, environment variable
@item $CVS_CLIENT_LOG
Used for debugging only in client-server
mode.  If set, everything sent to the server is logged
into @file{@code{$CVS_CLIENT_LOG}.in} and everything
sent from the server is logged into
@file{@code{$CVS_CLIENT_LOG}.out}.

@cindex CVS_SERVER_SLEEP, environment variable
@item $CVS_SERVER_SLEEP
Used only for debugging the server side in
client-server mode.  If set, delays the start of the
server child process the specified amount of
seconds so that you can attach to it with a debugger.

@cindex CVS_IGNORE_REMOTE_ROOT, environment variable
@item $CVS_IGNORE_REMOTE_ROOT
For @sc{cvs} 1.10 and older, setting this variable
prevents @sc{cvs} from overwriting the @file{CVS/Root}
file when the @samp{-d} global option is specified.
Later versions of @sc{cvs} do not rewrite
@file{CVS/Root}, so @code{CVS_IGNORE_REMOTE_ROOT} has no
effect.

@cindex COMSPEC, environment variable
@item $COMSPEC
Used under OS/2 only.  It specifies the name of the
command interpreter and defaults to @sc{cmd.exe}.

@cindex TMPDIR, environment variable
@item $TMPDIR
@cindex TMP, environment variable
@itemx $TMP
@cindex TEMP, environment variable
@itemx $TEMP
@cindex Temporary files, location of
@c This is quite nuts.  We don't talk about tempnam
@c or mkstemp which we sometimes use.  The discussion
@c of "Global options" is semi-incoherent.
@c I'm not even sure those are the only inaccuracies.
@c Furthermore, the conventions are
@c pretty crazy and they should be simplified.
Directory in which temporary files are located.
The @sc{cvs} server uses
@code{TMPDIR}.  @xref{Global options}, for a
description of how to specify this.
Some parts of @sc{cvs} will always use @file{/tmp} (via
the @code{tmpnam} function provided by the system).

On Windows NT, @code{TMP} is used (via the @code{_tempnam}
function provided by the system).

The @code{patch} program which is used by the @sc{cvs}
client uses @code{TMPDIR}, and if it is not set, uses
@file{/tmp} (at least with GNU patch 2.1).  Note that
if your server and client are both running @sc{cvs}
1.9.10 or later, @sc{cvs} will not invoke an external
@code{patch} program.
@end table

@node Compatibility
@appendix Compatibility between CVS Versions

@cindex CVS, versions of
@cindex Versions, of CVS
@cindex Compatibility, between CVS versions
@c We don't mention versions older than CVS 1.3
@c on the theory that it would clutter it up for the vast
@c majority of people, who don't have anything that old.
@c
The repository format is compatible going back to
@sc{cvs} 1.3.  But see @ref{Watches Compatibility}, if
you have copies of @sc{cvs} 1.6 or older and you want
to use the optional developer communication features.
@c If you "cvs rm" and commit using 1.3, then you'll
@c want to run "rcs -sdead <file,v>" on each of the
@c files in the Attic if you then want 1.5 and
@c later to recognize those files as dead (I think the
@c symptom if this is not done is that files reappear
@c in joins).  (Wait: the above will work but really to
@c be strictly correct we should suggest checking
@c in a new revision rather than just changing the
@c state of the head revision, shouldn't we?).
@c The old convert.sh script was for this, but it never
@c did get updated to reflect use of the RCS "dead"
@c state.
@c Note: this is tricky to document without confusing
@c people--need to carefully say what CVS version we
@c are talking about and keep in mind the distinction
@c between a
@c repository created with 1.3 and on which one now
@c uses 1.5+, and a repository on which one wants to
@c use both versions side by side (e.g. during a
@c transition period).
@c Wait, can't CVS just detect the case in which a file
@c is in the Attic but the head revision is not dead?
@c Not sure whether this should produce a warning or
@c something, and probably needs further thought, but
@c it would appear that the situation can be detected.
@c
@c We might want to separate out the 1.3 compatibility
@c section (for repository & working directory) from the
@c rest--that might help avoid confusing people who
@c are upgrading (for example) from 1.6 to 1.8.
@c
@c A minor incompatibility is if a current version of CVS
@c puts "Nfoo" into CVS/Tag, then CVS 1.9 or older will
@c see this as if there is no tag.  Seems to me this is
@c too obscure to mention.

The working directory format is compatible going back
to @sc{cvs} 1.5.  It did change between @sc{cvs} 1.3
and @sc{cvs} 1.5.  If you run @sc{cvs} 1.5 or newer on
a working directory checked out with @sc{cvs} 1.3,
@sc{cvs} will convert it, but to go back to @sc{cvs}
1.3 you need to check out a new working directory with
@sc{cvs} 1.3.

The remote protocol is interoperable going back to @sc{cvs} 1.5, but no
further (1.5 was the first official release with the remote protocol,
but some older versions might still be floating around).  In many
cases you need to upgrade both the client and the server to take
advantage of new features and bug fixes, however.

@c Perhaps should be saying something here about the
@c "D" lines in Entries (written by CVS 1.9; 1.8 and
@c older don't use them).  These are supposed to be
@c compatible in both directions, but I'm not sure
@c they quite are 100%.  One common gripe is if you
@c "rm -r" a directory and 1.9 gets confused, as it
@c still sees it in Entries.  That one is fixed in
@c (say) 1.9.6.  Someone else reported problems with
@c starting with a directory which was checked out with
@c an old version, and then using a new version, and
@c some "D" lines appeared, but not for every
@c directory, causing some directories to be skipped.
@c They weren't sure how to reproduce this, though.

@c ---------------------------------------------------------------------
@node Troubleshooting
@appendix Troubleshooting

If you are having trouble with @sc{cvs}, this appendix
may help.  If there is a particular error message which
you are seeing, then you can look up the message
alphabetically.  If not, you can look through the
section on other problems to see if your problem is
mentioned there.

@menu
* Error messages::              Partial list of CVS errors
* Connection::                  Trouble making a connection to a CVS server
* Other problems::              Problems not readily listed by error message
@end menu

@ignore
@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@c @node Bad administrative files
@appendixsec Bad administrative files

@c -- Give hints on how to fix them
@end ignore

@node Error messages
@appendixsec Partial list of error messages

Here is a partial list of error messages that you may
see from @sc{cvs}.  It is not a complete list---@sc{cvs}
is capable of printing many, many error messages, often
with parts of them supplied by the operating system,
but the intention is to list the common and/or
potentially confusing error messages.

The messages are alphabetical, but introductory text
such as @samp{cvs update: } is not considered in
ordering them.

In some cases the list includes messages printed by old
versions of @sc{cvs} (partly because users may not be
sure which version of @sc{cvs} they are using at any
particular moment).
@c If we want to start retiring messages, perhaps we
@c should pick a cutoff version (for example, no more
@c messages which are specific to versions before 1.9)
@c and then move the old messages to an "old messages"
@c node rather than deleting them completely.

@table @code
@c FIXME: What is the correct way to format a multiline
@c error message here?  Maybe @table is the wrong
@c choice?  Texinfo gurus?
@item @var{file}:@var{line}: Assertion '@var{text}' failed
The exact format of this message may vary depending on
your system.  It indicates a bug in @sc{cvs}, which can
be handled as described in @ref{BUGS}.

@item cvs @var{command}: authorization failed: server @var{host} rejected access
This is a generic response when trying to connect to a
pserver server which chooses not to provide a
specific reason for denying authorization.  Check that
the username and password specified are correct and
that the @code{CVSROOT} specified is allowed by @samp{--allow-root}
in @file{inetd.conf}.  See @ref{Password authenticated}.

@item cvs @var{command}: conflict: removed @var{file} was modified by second party
This message indicates that you removed a file, and
someone else modified it.  To resolve the conflict,
first run @samp{cvs add @var{file}}.  If desired, look
at the other party's modification to decide whether you
still want to remove it.  If you don't want to remove
it, stop here.  If you do want to remove it, proceed
with @samp{cvs remove @var{file}} and commit your
removal.
@c Tests conflicts2-142b* in sanity.sh test for this.

@item cannot change permissions on temporary directory
@example
Operation not permitted
@end example
This message has been happening in a non-reproducible,
occasional way when we run the client/server testsuite,
bot