Col filters out reverse (and half reverse) line feeds so the output is in
the correct order with only forward and half forward line feeds, and
replaces white-space characters with tabs where possible. This can be
useful in processing the output of nroff(1)
Col reads from standard input and writes to standard output.
The options are as follows:
Do not output any backspaces, printing only the last character
written to each column position.
Forward half line feeds are permitted (’’fine’’ mode). Normally
characters printed on a half line boundary are printed on the following
Force unknown control sequences to be passed through unchanged.
Normally, col will filter out any control sequences from the input
other than those recognized and interpreted by itself, which are
Output multiple spaces instead of tabs.
Buffer at least num lines in memory. By default, 128 lines are
The control sequences for carriage motion that col understands and their
decimal values are listed in the following table:
reverse line feed (escape then 7)
half reverse line feed (escape then 8)
half forward line feed (escape then 9)
moves back one column (8); ignored in the first column
carriage return (13)
forward line feed (10); also does carriage return
shift to normal character set (15)
shift to alternate character set (14)
moves forward one column (32)
moves forward to next tab stop (9)
reverse line feed (11)
All unrecognized control characters and escape sequences are discarded.
Col keeps track of the character set as characters are read and makes
sure the character set is correct when they are output.
If the input attempts to back up to the last flushed line, col will display
a warning message.