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COL(1)                  NetBSD General Commands Manual                  COL(1)


NAME

     col -- filter reverse line feeds from input


SYNOPSIS

     col [-bfhpx] [-l num]


DESCRIPTION

     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.

     The col utility reads from the standard input and writes to the standard
     output.

     The options are as follows:

     -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 fol-
     lows:

     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 dis-
     play a warning message.


ENVIRONMENT

     The LANG, LC_ALL and LC_CTYPE environment variables affect the execution
     of col as described in environ(7).


EXIT STATUS

     The col utility exits 0 on success, and >0 if an error occurs.


EXAMPLES

     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


SEE ALSO

     expand(1)


STANDARDS

     The col utility conforms to Version 2 of the Single UNIX Specification
     (``SUSv2'').


HISTORY

     A col command appeared in Version 6 AT&T UNIX.

NetBSD 10.1                    November 1, 2020                    NetBSD 10.1