col(1)                                                     col(1)



NAME
     col - filters text containing printer control sequences  for
     use at a display device

SYNOPSIS
     col [-b] [-f] [-p] [-x]

ARGUMENTS
     -b   Causes col to assume that the output device in use is
          not capable of backspacing.  In this case, if two or
          more characters are to appear in the same place, only
          the last one read will be output.

     -f   Suppresses the movement of text.  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.  When this option is used, the output from
          col may contain forward half-linefeeds (ESCAPE-9), but
          will still never contain either kind of reverse line
          motion.

     -p   Causes col to generate unknown escape sequences as
          regular characters, subject to overprinting from
          reverse line motions.  The use of this option is highly
          discouraged unless the user is fully aware of the
          textual position of the escape sequences.  Normally,
          col will ignore any unknown escape sequences found in
          its input.

     -x   Does not convert white space to tabs on output wherever
          possible to shorten printing time.

DESCRIPTION
     col reads from the standard input and writes onto the
     standard output.  It performs the line overlays implied by
     reverse linefeeds (ASCII code ESCAPE-7), and by forward and
     reverse half-linefeeds (ESCAPE-9 and (ESCAPE-8). The col
     command is particularly useful for filtering multicolumn
     output made with the .rt command of nroff and output
     resulting from use of the tbl(1) preprocessor.

     The ASCII control characters SO (\016) and SI (\017) are
     assumed by col to start and end text in an alternate
     character set.  The character set to which each input
     character belongs is remembered, and on output SI and SO
     characters are generated as appropriate to ensure that each
     character is printed in the correct character set.

     On input, the only control characters accepted are space,
     backspace, tab, return, SI , SO , T (\013), and escape
     followed by 7, 8, or 9.  The VT character is an alternate



January 1992                                                    1

col(1)                                                     col(1)



     form of full reverse linefeed, included for compatibility
     with some earlier programs of this type.  All other
     nonprinting characters are ignored.

EXAMPLES
     The command:

        nroff -mm filea | col

     pipes multicolumn nroff output through the col filter to
     enable proper creation of columns.

LIMITATIONS
     Cannot back up more than 128 lines.

     Allows at most 800 characters, including backspaces, on a
     line.

     Local vertical motions that would result in backing up over
     the first line of the document are ignored.  As a result,
     the first line must not have any superscripts.

NOTES
     The input format accepted by col matches the output produced
     by nroff with either the -T37 or -Tlp options.  Use -T37
     (and the -f option of col) if the ultimate disposition of
     the output of col will be a device that can interpret half-
     line motions, and -Tlp otherwise.

FILES
     /usr/bin/col
          Executable file

SEE ALSO
     colcrt(1), nroff(1), tbl(1)




















2                                                    January 1992