Filter reverse line feeds from input.
Syntax
col [-bfhpx] [-l num]
Key:
-b Do not output any backspaces, printing only the last character written to each column position.
-f Forward half line feeds are permitted ('fine' mode).
Normally characters printed on a half line boundary are printed on the following line.
-h Do not output multiple spaces instead of tabs (default).
-l num Buffer at least num lines in memory. By default, 128 lines are buffered.
-p 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 listed below.
-x Output multiple spaces instead of tabs.
In the input stream, col understands both the escape sequences of the form escape-digit mandated by Version 2 of the Single UNIX Specification (“SUSv2”) and the traditional BSD format escape-control-character.
The control sequences for carriage motion and their ASCII values are as follows:
ESC-BELL reverse line feed (escape then bell). ESC-7 reverse line feed (escape then 7). ESC-BACKSPACE half reverse line feed (escape then backspace). ESC-8 half reverse line feed (escape then 8). ESC-TAB half forward line feed (escape than tab). ESC-9 half forward line feed (escape then 9). In -f mode, this sequence may also occur in the output stream. backspace moves back one column (8); ignored in the first column carriage return (13) newline forward line feed (10); also does carriage return shift in shift to normal character set (15) shift out shift to alternate character set (14) space moves forward one column (32) tab moves forward to next tab stop (9) vertical tab reverse line feed (11)
All unrecognized control characters and escape sequences are discarded.
The col utility 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.
The LANG, LC_ALL and LC_CTYPE environment variables affect the execution of col as described in environ(7).
The col utility exits 0 on success, and >0 if an error occurs.
We can use col to filter the output of man(1) and remove the backspace characters ( ^H ) before searching for some text:
$ man ls | col -b | grep HISTORY
“A good column is one that sells paper. It doesn't matter how beautifully it is written and how much you admire the author... if it doesn't sell any papers, it's not a good column. It's a terrible yardstick to use, but in the newspaper business, that's the whole thing” ~ Herb Caen
Local man page: col - Command line help page on your local machine.
expand - Convert tabs to spaces.
less - Display output one screen at a time.