col - filter reverse line feeds
Col reads the standard input and writes the standard output. It performs the line over-
lays implied by reverse line feeds (ESC-7 in ASCII) 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.
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.
If the -b option is given, col assumes that the output device in use is not capable of
backspacing. In this case, if several characters are to appear in the same place, only
the last one read will be taken.
The control characters SO (ASCII code 017), and SI (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 generated
where necessary to maintain the correct treatment of each character.
Col normally converts white space to tabs to shorten printing time. If the -x option is
given, this conversion is suppressed.
All control characters are removed from the input except space, backspace, tab, return,
newline, ESC (033) followed by one of 789, SI, SO, and VT (013). This last character is
an alternate form of full reverse line feed, for compatibility with some other hardware
conventions. All other non-printing characters are ignored.
troff(1), tbl(1), greek(1)
Can't back up more than 128 lines.
No more than 800 characters, including backspaces, on a line.