COLCRT(1)                        User Commands                       COLCRT(1)

NAME
       colcrt - filter nroff output for CRT previewing

SYNOPSIS
       colcrt [options] [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 new lines in between the normal output lines.

OPTIONS
       -, --no-underlining
           Suppress all underlining. This option is especially useful for
           previewing allboxed tables from tbl(1).

       -2, --half-lines
           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 partially invisible.

       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

HISTORY
       The colcrt command appeared in 3.0BSD.

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.

EXAMPLES
       A typical use of colcrt would be:

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

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

REPORTING BUGS
       For bug reports, use the issue tracker at
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY
       The colcrt command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.40                   2024-04-06                         COLCRT(1)