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COL(1) NetBSD General Commands Manual COL(1)
Powered by man-cgi (2020-09-24).
Maintained for NetBSD
by Kimmo Suominen.
Based on man-cgi by Panagiotis Christias.
col -- filter reverse line feeds from input
col [-bfhpx] [-l num]
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.
The col utility reads from the standard input and writes to the standard
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
-h Do not output multiple spaces instead of tabs (default).
-l num Buffer at least num lines in memory. By default, 128 lines are
-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.
In the input stream, col understands both the escape sequences of the
form escape-digit mandated by Version 2 of the Single UNIX Specification
(``SUSv2'') and the traditional BSD format escape-control-character. The
control sequences for carriage motion and their ASCII values are as fol-
ESC-BELL reverse line feed (escape then bell).
ESC-7 reverse line feed (escape then 7).
ESC-BACKSPACE half reverse line feed (escape then backspace).
ESC-8 half reverse line feed (escape then 8).
ESC-TAB half forward line feed (escape than tab).
ESC-9 half forward line feed (escape then 9). In -f mode,
this sequence may also occur in the output stream.
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 dis-
play a warning message.
The LANG, LC_ALL and LC_CTYPE environment variables affect the execution
of col as described in environ(7).
The col utility exits 0 on success, and >0 if an error occurs.
We can use col to filter the output of man(1) and remove the backspace
characters ( ^H ) before searching for some text:
man ls | col -b | grep HISTORY
The col utility conforms to Version 2 of the Single UNIX Specification
A col command appeared in Version 6 AT&T UNIX.
NetBSD 9.99 November 1, 2020 NetBSD 9.99