COL(1)                               SysV                               COL(1)



NAME
     col - filter reverse line feeds

SYNOPSIS
     col [ -bfpx ]

DESCRIPTION
     col reads the standard input and writes the standard output.  It performs
     the line overlays implied by reverse line feeds (ESC-7 in ASCII) and by
     forward and reverse half line feeds (ESC-9 and ESC-8).  col is
     particularly useful for filtering multicolumn output made with the .rt
     command of nroff(1) and output resulting from using the tbl(1)
     preprocessor.

     Although col accepts half line motions in its input, it normally does not
     emit them on output.  Instead, it moves text that would appear between
     lines to the next lower full line boundary.

     The control characters SO (ASCII code 017), and SI (016) are assumed to
     start and end text in an alternate character set.  col remembers the
     character set (primary or alternate) associated with each printing
     character read.  On output, col generates SO and SI characters where
     necessary to maintain the correct treatment of each character.

     All control characters are removed from the input except space,
     backspace, tab, return, newline, and ESC (033) followed by one of 7, 8,
     9, SI, SO, and VT (013).  This last character is an alternate form of
     full reverse line feed, for compatibility with some other hardware
     conventions.  All other non-printing characters are ignored.

OPTIONS
     -b        Assumes that the output device in use is not capable of
               backspacing.  If two or more characters are to appear in the
               same place, only the last character read will be taken.

     -f        Allows the output to contain half-line feeds (ESC-9).  Even
               with this option it will never contain either kind of reverse
               line motion.

     -p        Causes col to output unknown escape sequences as regular
               characters, subject to overprinting from reverse line motions.

     -x        Converts white space to tabs to shorten printing time.

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

WARNINGS
     The use of the -p option is highly discouraged unless the user is fully
     aware of the textual positions of the escape sequences.

BUGS
     col can't back up more than 128 lines.
     There can be no more than 800 characters, including backspaces, on a
     line.

SEE ALSO
     nroff(1), tbl(1)