COL(1)                                                                  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 per‐
       forms 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) pre‐
       processor.

       Although _c_o_l 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.  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 device 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  neces‐
       sary 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 character is an alternate form of full
       reverse  line  feed, for compatibility with some other hardware conven‐
       tions.  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.



7th Edition                      May 16, 1986                           COL(1)