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.\"	@(#)rs.1	8.2 (Berkeley) 12/30/93
.\" $FreeBSD$
.\"
.Dd February 25, 2011
.Dt RS 1
.Os
.Sh NAME
.Nm rs
.Nd reshape a data array
.Sh SYNOPSIS
.Nm
.Oo
.Fl Oo Cm csCS Oc Ns Op Ar x
.Oo Cm kKgGw Oc Ns Op Ar N
.Cm tTeEnyjhHmz
.Oc
.Op Ar rows Op Ar cols
.Sh DESCRIPTION
The
.Nm
utility reads the standard input, interpreting each line as a row
of blank-separated entries in an array,
transforms the array according to the options,
and writes it on the standard output.
With no arguments it transforms stream input into a columnar
format convenient for terminal viewing.
.Pp
The shape of the input array is deduced from the number of lines
and the number of columns on the first line.
If that shape is inconvenient, a more useful one might be
obtained by skipping some of the input with the
.Fl k
option.
Other options control interpretation of the input columns.
.Pp
The shape of the output array is influenced by the
.Ar rows
and
.Ar cols
specifications, which should be positive integers.
If only one of them is a positive integer,
.Nm
computes a value for the other which will accommodate
all of the data.
When necessary, missing data are supplied in a manner
specified by the options and surplus data are deleted.
There are options to control presentation of the output columns,
including transposition of the rows and columns.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl c Ns Ar x
Input columns are delimited by the single character
.Ar x .
A missing
.Ar x
is taken to be `^I'.
.It Fl s Ns Ar x
Like
.Fl c ,
but maximal strings of
.Ar x
are delimiters.
.It Fl C Ns Ar x
Output columns are delimited by the single character
.Ar x .
A missing
.Ar x
is taken to be `^I'.
.It Fl S Ns Ar x
Like
.Fl C ,
but padded strings of
.Ar x
are delimiters.
.It Fl t
Fill in the rows of the output array using the columns of the
input array, that is, transpose the input while honoring any
.Ar rows
and
.Ar cols
specifications.
.It Fl T
Print the pure transpose of the input, ignoring any
.Ar rows
or
.Ar cols
specification.
.It Fl k Ns Ar N
Ignore the first
.Ar N
lines of input.
.It Fl K Ns Ar N
Like
.Fl k ,
but print the ignored lines.
.It Fl g Ns Ar N
The gutter width (inter-column space), normally 2, is taken to be
.Ar N .
.It Fl G Ns Ar N
The gutter width has
.Ar N
percent of the maximum column width added to it.
.It Fl e
Consider each line of input as an array entry.
.It Fl n
On lines having fewer entries than the first line,
use null entries to pad out the line.
Normally, missing entries are taken from the next line of input.
.It Fl y
If there are too few entries to make up the output dimensions,
pad the output by recycling the input from the beginning.
Normally, the output is padded with blanks.
.It Fl h
Print the shape of the input array and do nothing else.
The shape is just the number of lines and the number of
entries on the first line.
.It Fl H
Like
.Fl h ,
but also print the length of each line.
.It Fl j
Right adjust entries within columns.
.It Fl w Ns Ar N
The width of the display, normally 80, is taken to be the positive
integer
.Ar N .
.It Fl m
Do not trim excess delimiters from the ends of the output array.
.It Fl z
Adapt column widths to fit the largest entries appearing in them.
.El
.Pp
With no arguments,
.Nm
transposes its input, and assumes one array entry per input line
unless the first non-ignored line is longer than the display width.
Option letters which take numerical arguments interpret a missing
number as zero unless otherwise indicated.
.Sh EXAMPLES
The
.Nm
utility can be used as a filter to convert the stream output
of certain programs (e.g.,
.Xr spell 1 ,
.Xr du 1 ,
.Xr file 1 ,
.Xr look 1 ,
.Xr nm 1 ,
.Xr who 1 ,
and
.Xr wc 1 )
into a convenient ``window'' format, as in
.Bd -literal -offset indent
% who | rs
.Ed
.Pp
This function has been incorporated into the
.Xr ls 1
program, though for most programs with similar output
.Nm
suffices.
.Pp
To convert stream input into vector output and back again, use
.Bd -literal -offset indent
% rs 1 0 | rs 0 1
.Ed
.Pp
A 10 by 10 array of random numbers from 1 to 100 and
its transpose can be generated with
.Bd -literal -offset indent
% jot \-r 100 | rs 10 10 | tee array | rs \-T > tarray
.Ed
.Pp
In the editor
.Xr vi 1 ,
a file consisting of a multi-line vector with 9 elements per line
can undergo insertions and deletions,
and then be neatly reshaped into 9 columns with
.Bd -literal -offset indent
:1,$!rs 0 9
.Ed
.Pp
Finally, to sort a database by the first line of each 4-line field, try
.Bd -literal -offset indent
% rs \-eC 0 4 | sort | rs \-c 0 1
.Ed
.Sh SEE ALSO
.Xr jot 1 ,
.Xr pr 1 ,
.Xr sort 1 ,
.Xr vi 1
.Sh HISTORY
The
.Nm
utility first appeared in
.Bx 4.2 .
.Sh BUGS
.Bl -item
.It
Handles only two dimensional arrays.
.It
The algorithm currently reads the whole file into memory,
so files that do not fit in memory will not be reshaped.
.It
Fields cannot be defined yet on character positions.
.It
Re-ordering of columns is not yet possible.
.It
There are too many options.
.It
Multibyte characters are not recognized.
.It
Lines longer than
.Dv LINE_MAX
(2048) bytes are not processed and result in immediate termination of
.Nm .
.El