COL(1) (Directory and File Management Utilities) COL(1)
NAME
col - filter reverse line-feeds
SYNOPSIS
col [-b] [-f] [-x] [-p]
DESCRIPTION
col reads from the standard input and writes onto the
standard output. It performs the line overlays implied by
reverse line feeds (ASCII code ESC-7), and by forward and
reverse half-line-feeds (ESC-9 and ESC-8). col is
particularly useful for filtering multicolumn output made
with the .rt command of nroff and output resulting from use
of the tbl(1) preprocessor.
If the -b option is given, col assumes that the output
device in use is not capable of backspacing. In this case,
if two or more characters are to appear in the same place,
only the last one read will be output.
Although col accepts half-line motions in its input, it
normally does not emit them on output. Instead, text that
would appear between lines is moved to the next lower full-
line boundary. This treatment can be suppressed by the -f
(fine) option; in this case, the output from col may contain
forward half-line-feeds (ESC-9), but will still never
contain either kind of reverse line motion.
Unless the -x option is given, col will convert white space
to tabs on output wherever possible to shorten printing
time.
The ASCII control characters SO (\017) and SI (\016) are
assumed by col to start and end text in an alternate
character set. The character set to which each input
character belongs is remembered, and on output SI and SO
characters are generated as appropriate to ensure that each
character is printed in the correct character set.
On input, the only control characters accepted are space,
Page 1 May 1989
COL(1) (Directory and File Management Utilities) COL(1)
backspace, tab, return, new-line, SI, SO, VT (\013), and ESC
followed by 7, 8, or 9. The VT character is an alternate
form of full reverse line-feed, included for compatibility
with some earlier programs of this type. All other non-
printing characters are ignored.
Normally, col will ignore any escape sequences unknown to it
that are found in its input; the -p option may be used to
cause col to output these sequences as regular characters,
subject to overprinting from reverse line motions. The use
of this option is highly discouraged unless the user is
fully aware of the textual position of the escape sequences.
NOTES
The input format accepted by col matches the output produced
by nroff with either the -T37 or -Tlp options. Use -T37
(and the -f option of col) if the ultimate disposition of
the output of col will be a device that can interpret half-
line motions, and -Tlp otherwise.
BUGS
Cannot back up more than 128 lines.
Allows at most 800 characters, including backspaces, on a
line.
Local vertical motions that would result in backing up over
the first line of the document are ignored. As a result,
the first line must not have any superscripts.
Page 2 May 1989