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 2.39.3                                           2023-10-23                                                  COLCRT(1)