


COL(1)		    UNIX Programmer's Manual		   COL(1)



NAME
     col - filter reverse line feeds

SYNOPSIS
     col [ -bfh ]

DESCRIPTION
     _C_o_l 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).  _C_o_l is particularly useful for filtering
     multicolumn output made with the `.rt' command of _n_r_o_f_f and
     output resulting from use of the _t_b_l(1) preprocessor.

     Although _c_o_l accepts half line motions in its input, it nor-
     mally does not emit them on output.  Instead, text that
     would appear between lines is moved to the next lower full
     line boundary.  This treatment can be suppressed by the -f
     (fine) option; in this case the output from _c_o_l may contain
     forward half line feeds (ESC-9), but will still never con-
     tain either kind of reverse line motion.

     If the -b option is given, _c_o_l assumes that the output dev-
     ice in use is not capable of backspacing.	In this case, if
     several characters are to appear in the same place, only the
     last one read will be taken.

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

     If the -h option is given, _c_o_l converts white space to tabs
     to shorten printing time.

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

SEE ALSO
     troff(1), tbl(1)

BUGS
     Can't back up more than 128 lines.
     No more than 800 characters, including backspaces, on a
     line.




Printed 11/26/99	  May 16, 1986				1



