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COLCRT(1) User Commands COLCRT(1)


colcrt - filter nroff output for CRT previewing


colcrt [options] [file...]


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.


-, --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.
Display version information and exit.
Display help text and exit.


The colcrt command appeared in 3.0BSD.


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.


A typical use of colcrt would be:

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


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


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

September 2011 util-linux