colcrt(1) — Linux manual page


COLCRT(1)                     User Commands                    COLCRT(1)

NAME         top

       colcrt - filter nroff output for CRT previewing

SYNOPSIS         top

       colcrt [options] [file...]

DESCRIPTION         top

       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

OPTIONS         top

       -, --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 invisible.

       -V, --version
              Display version information and exit.

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

HISTORY         top

       The colcrt command appeared in 3.0BSD.

BUGS         top

       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         top

       A typical use of colcrt would be:

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

SEE ALSO         top

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

AVAILABILITY         top

       The colcrt command is part of the util-linux package and is
       available from Linux Kernel Archive 

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found
       at ⟨⟩.  If you
       have a bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2021-03-21.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-19.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
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       information in this COLOPHON (which is not part of the original
       manual page), send a mail to

util-linux                   September 2011                    COLCRT(1)

Pages that refer to this page: ul(1)