Linux "col" Command Line Options and Examples
filter reverse line feeds from input
The col utility filters out reverse (and half reverse) line feeds so that 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) and tbl(1). The col utility reads from the standard input and writes to the standard output.
Usage:
col [-bfhpx] [-l num]
Command Line Options:
-b
Do not output any backspaces, printing only the last character written to each column position.
col -b ...
-h
Do not output multiple spaces instead of tabs (default).
col -h ...
-l
num Buffer at least num lines in memory. By default, 128 lines are buffered.
col -l ...
-x
In the input stream, col understands both the escape sequences of the form escape-digit mandated by Version 2 of the Single UNIXSpecification (“SUSv2”) and the traditional BSD format escape-control-character. The control sequences for carriage motion and theirASCII 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 columncarriage return (13)newline forward line feed (10); also does carriage returnshift 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 out‐put.If the input attempts to back up to the last flushed line, col will display a warning message.ENVIRONMENTThe LANG, LC_ALL and LC_CTYPE environment variables affect the execution of col as described in environ(7).EXIT STATUSThe col utility exits 0 on success, and >0 if an error occurs.
col -x ...