NAME
rs
—
reshape a data array
SYNOPSIS
rs |
[- [csCS ][x]
[kKgGw ][N]
tTeEnyjhHmz ] [rows
[cols]] |
DESCRIPTION
Thers
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.
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
-k
option. Other options control interpretation of
the input columns.
The shape of the output array is influenced by the
rows and cols specifications,
which should be positive integers. If only one of them is a positive
integer, rs
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.
The following options are available:
-c
x- Input columns are delimited by the single character x. A missing x is taken to be `^I'.
-s
x- Like
-c
, but maximal strings of x are delimiters. -C
x- Output columns are delimited by the single character x. A missing x is taken to be `^I'.
-S
x- Like
-C
, but padded strings of x are delimiters. -t
- Fill in the rows of the output array using the columns of the input array, that is, transpose the input while honoring any rows and cols specifications.
-T
- Print the pure transpose of the input, ignoring any rows or cols specification.
-k
N- Ignore the first N lines of input.
-K
N- Like
-k
, but print the ignored lines. -g
N- The gutter width (inter-column space), normally 2, is taken to be N.
-G
N- The gutter width has N percent of the maximum column width added to it.
-e
- Consider each line of input as an array entry.
-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.
-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.
-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.
-H
- Like
-h
, but also print the length of each line. -j
- Right adjust entries within columns.
-w
N- The width of the display, normally 80, is taken to be the positive integer N.
-m
- Do not trim excess delimiters from the ends of the output array.
-z
- Adapt column widths to fit the largest entries appearing in them.
With no arguments, rs
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.
EXAMPLES
The rs
utility can be used as a filter to
convert the stream output of certain programs (e.g.,
spell(1), du(1),
file(1), look(1),
nm(1), who(1), and
wc(1)) into a convenient ``window'' format, as in
% who | rs
This function has been incorporated into the
ls(1)
program, though for most programs with similar output
rs
suffices.
To convert stream input into vector output and back again, use
% rs 1 0 | rs 0 1
A 10 by 10 array of random numbers from 1 to 100 and its transpose can be generated with
% jot -r 100 | rs 10 10 | tee array | rs -T > tarray
In the editor 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
:1,$!rs 0 9
Finally, to sort a database by the first line of each 4-line field, try
% rs -eC 0 4 | sort | rs -c 0 1
SEE ALSO
HISTORY
The rs
utility first appeared in
4.2BSD.
AUTHORS
John A. Kunze
BUGS
- Handles only two dimensional arrays.
- The algorithm currently reads the whole file into memory, so files that do not fit in memory will not be reshaped.
- Fields cannot be defined yet on character positions.
- Re-ordering of columns is not yet possible.
- There are too many options.
- Multibyte characters are not recognized.
- Lines longer than
LINE_MAX
(2048) bytes are not processed and result in immediate termination ofrs
.