colcrt(1)                                               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 destructive.  Half-line characters and
          underlining (changed to dashing ``-'') are placed on
          newlines in between the normal output lines.

          The optional - suppresses all underlining.  It is especially
          useful for previewing allboxed tables from tbl(1).

          The option -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 flag option is useful for sending output to
          the line printer when the output contains superscripts and
          subscripts which would otherwise be invisible.

          A typical use of colcrt would be

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

     FILES
          /usr/ucb/colcrt

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

     BUGS
          Should fold underlines onto blanks even with the ``-'' flag
          option so that a true underline character would show; if we
          did this, however, colcrt wouldn't get rid of cu'd
          underlining completely.

          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.






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