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 partially invisible.

-h, --help

Display help text and exit.

-V, --version

Print version 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)

For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

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/.

2025-01-09 util-linux 2.40.3