col -- filter reverse line-feeds


col [-b] [-f] [-x] [-p]


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(1bsd) 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 processed are space, 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.


language-specific message file (See LANG on environ(5).)


ascii(5), nroff(1bsd), tbl(1bsd)


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.

col cannot back up more than 128 lines or handle more than 800 characters per 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.

© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004