col(1) General Commands Manual col(1)
Name
col - filter reverse line feeds
Syntax
col [-options]
Description
The command reads the standard input and writes the standard output. It performs the line overlays implied by reverse line feeds (ESC-7 in
ASCII) and by forward and reverse half line feeds (ESC-9 and ESC-8, respectively). The command is particularly useful for filtering multi-
column output made with the command of and for filtering output resulting from the preprocessor.
Although accepts half line motions in its input, it does not normally output them. Instead, text that would appear between lines is moved
to the next lower full line boundary.
The control characters SO (ASCII code 017) and SI (ASCII code 016) are assumed to start and end text in an alternate character set. The
character set (primary or alternate) associated with each printing character read is remembered. On output, SO and SI characters are gen-
erated where necessary to maintain the correct treatment of each character.
The command normally converts white space to tabs to shorten printing time. If the -h option is given, this conversion is suppressed.
On input, the only control characters accepted are <space>, <backspace>, <tab>, <return>, <newline>, etc... The VT character is an alter-
nate form of full reverse linefeed, included for compatibility with earlier programs of this type. All other non-printing characters are
ignored.
Options
-b Assumes that the output device does not have backspacing.
-f Suppresses moving half lines to the next full line.
-h Suppresses conversion of white space to tabs.
-p Forces through unchanged any unknown escape sequences that are found in its input. This option should be used with care.
-x Suppresses conversion of white space to tabs (same as -h).
Restrictions
Cannot back up more than 128 lines.
No more than 800 characters, including backspaces, on a line.
See Also
tbl(1), nroff(1)
col(1)