COL(CT) XENIX System V COL(CT)
Name
col - Filters reverse linefeeds.
Syntax
col [ -bfxp ]
Description
col prepares output from processes, such as the text
formatter nroff(CT), for output on devices that limit or do
not allow reverse or half-line motions. col is typically
used to process nroff output text that contains tables
generated by the tbl program. A typical command line might
be:
tbl file | nroff | col | lpr
col takes the following options:
-b Assumes the output device in use is not capable of
backspacing. If two or more characters appear in the
same place, col outputs the last character read.
-f Allows forward half linefeeds. If not given, col
accepts half line motions in its input, but text that
would appear between lines is moved down to the next
full line. Reverse full and half linefeeds are never
allowed with this option.
-x Prevents conversion of whitespace to tabs on output.
col normally converts whitespace to tabs wherever
possible to shorten printing time.
-p Causes col to ignore unknown escape sequences found in
its input and pass them to the output as regular
characters. Because these characters are subject to
overprinting from reverse line motions, the use of this
option is discouraged unless the user is fully aware of
the position of the escape sequences.
col assumes that the ASCII control characters SO (octal 016)
and SI (octal 017) start and end text in an alternate
character set. If you have a reverse linefeed (ESC 7),
reverse half linefeed (ESC 8), or forward half linefeed (ESC
9), within an SI-SO sequence, the ESC 7, 8 and 9 are still
recognized as line motions.
On input, the only control characters col accepts are space,
backspace, tab, return, newline, reverse linefeed (ESC 7),
reverse half linefeed (ESC 8), forward half linefeed (ESC
9), alternate character start(SI), alternate character end
(SO), and vertical tag (VT). (The VT character is an
alternate form of full reverse linefeed, included for
Page 1 (printed 8/7/87)
COL(CT) XENIX System V COL(CT)
compatibility with some earlier programs of this type.) All
other nonprinting characters are ignored.
See Also
nroff(CT), tbl(CT)
Notes
col cannot back up more than 128 lines.
col allows at most 800 characters, including backspaces, on
a line.
Vertical motions that would back up over the first line of
the document are ignored. Therefore, the first line must
not contain any superscripts.
Page 2 (printed 8/7/87)