# colcrt

## 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**
               Display version and exit.
    


## 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**
    


## 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/>. This page is
           part of the _util-linux_ (a random collection of Linux utilities)
           project. Information about the project can be found at 
           ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
           bug report for this manual page, send it to
           util-linux@vger.kernel.org. This page was obtained from the
           project's upstream Git repository
           ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
           2025-08-11. (At that time, the date of the most recent commit that
           was found in the repository was 2025-08-05.) 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 the page,
           or you have corrections or improvements to the information in this
           COLOPHON (which is _not_ part of the original manual page), send a
           mail to man-pages@man7.org
    
    util-linux 2.42-start-521-ec46  2025-08-09                      _COLCRT_(1)
    


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