NAME¶
col —
filter reverse line feeds from
input
SYNOPSIS¶
DESCRIPTION¶
The
col utility filters out reverse (and half reverse) line
feeds so that 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).
The
col utility reads from the standard input and writes to
the 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.
- -h
- Do not output multiple spaces instead of tabs
(default).
- -l
num
- Buffer at least num lines in memory.
By default, 128 lines are buffered.
- -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.
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.
The
col utility 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.
ENVIRONMENT¶
The
LANG
,
LC_ALL
and
LC_CTYPE
environment variables affect the execution of
col as described in
environ(7).
EXIT STATUS¶
The
col utility exits 0 on success, and >0 if an
error occurs.
SEE ALSO¶
colcrt(1),
expand(1),
nroff(1),
tbl(1)
STANDARDS¶
The
col utility conforms to
Version 2 of
the Single UNIX Specification (“SUSv2”).
HISTORY¶
A
col command appeared in
Version 6
AT&T UNIX.