NAME
col - filter reverse line feeds from input
SYNOPSIS
col [-bfpx ] [-l num ]
DESCRIPTION
Col filters out reverse (and half
reverse) line feeds so the output is in the correct order with only
forward and half forward line feeds, and replaces white-space
characters with tabs where possible. This can be useful in
processing the output of nroff(1) and
tbl(1).
Col reads from standard input and writes to standard
output.
The options are as follows:
- -b
- Do not output any backspaces, printing only the last character
written to each column position.
- -f
- Forward half line feeds are permitted (``fine'' mode). Normally
characters printed on a half line boundary are printed on the
following line.
- -p
- Force unknown control sequences to be passed through unchanged.
Normally, col will filter out any control sequences from the
input other than those recognized and interpreted by itself, which
are listed below.
- -x
- Output multiple spaces instead of tabs.
- -l num
- Buffer at least num lines in memory. By default, 128
lines are buffered.
The control sequences for carriage motion that col
understands and their decimal values are listed in the following
table:
- ESC-7
- reverse line feed (escape then 7)
- ESC-8
- half reverse line feed (escape then 8)
- ESC-9
- half forward line feed (escape then 9)
- backspace
- moves back one column (8); ignored in the first column
- carriage return
- (13)
- newline
- forward line feed (10); also does carriage return
- shift in
- shift to normal character set (15)
- shift out
- shift to alternate character set (14)
- space
- moves forward one column (32)
- tab
- moves forward to next tab stop (9)
- vertical tab
- reverse line feed (11)
All unrecognized control characters and escape sequences are
discarded.
Col keeps track of the character set as characters are
read and makes sure the character set is correct when they are
output.
If the input attempts to back up to the last flushed line,
col will display a warning message.
SEE ALSO
expand(1),
nroff(1),
tbl(1)
STANDARDS
The col utility conforms to the Single
UNIX Specification, Version 2. The -l option is an extension
to the standard.
HISTORY
A col command appeared in Version 6 AT&T
UNIX.