COLCRT(1)                    UNIX Reference Manual                   COLCRT(1)

NAME
     colcrt - filter nroff output for CRT previewing

SYNOPSIS
     colcrt [-] [-2] [file ...]

DESCRIPTION
     Colcrt provides virtual half-line and reverse line feed sequences for
     terminals without such capability, and on which overstriking is destruc-
     tive.  Half-line characters and underlining (changed to dashing `-') are
     placed on new lines in between the normal output lines.

     Available options:

     -       Suppress all underlining.  This option is especially useful for
             previewing allboxed tables from tbl(1).

     -2      Causes all half-lines to be printed, effectively double spacing
             the output.  Normally, a minimal space output format is used
             which will suppress empty lines.  The program never suppresses
             two consecutive empty lines, however.  The -2 option is useful
             for sending output to the line printer when the output contains
             superscripts and subscripts which would otherwise be invisible.

EXAMPLES
     A typical use of colcrt would be

     tbl exum2.n | nroff -ms | colcrt - | more

SEE ALSO
     nroff(1),  troff(1),  col(1),  more(1),  ul(1)

BUGS
     Should fold underlines onto blanks even with the `-' option so that a
     true underline character would show.

     Can't back up more than 102 lines.

     General overstriking is lost; as a special case `|' overstruck with `-'
     or underline becomes `+'.

     Lines are trimmed to 132 characters.

     Some provision should be made for processing superscripts and subscripts
     in documents which are already double-spaced.

HISTORY
     The colcrt command appeared in 3.0BSD.

3rd Berkeley Distribution        June 30, 1993                               1