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.

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)

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.

HISTORY         top

       The colcrt command appeared in 3.0BSD.

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
       2017-09-15.  If you discover any rendering problems in this HTML ver‐
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       ual page), send a mail to

util-linux                     September 2011                      COLCRT(1)

Pages that refer to this page: ul(1)