COLCRT(1) BSD General Commands Manual COLCRT(1)
colcrt — filter nroff output for CRT previewing
colcrt [-] [-2] [file …]
The colcrt utility provides virtual half-line and reverse line feed
sequences for terminals without such capability, and on which overstrik‐
ing is destructive. Half-line characters and underlining (changed to
dashing `-‘) are placed on new lines in between the normal output lines.
The following options are available:
– Suppress all underlining. This option is especially useful for
previewing allboxed tables from tbl.
-2 Cause 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.
The LANG, LC_ALL and LC_CTYPE environment variables affect the execution
of colcrt as described in environ(7).
The colcrt utility exits 0 on success, and >0 if an error occurs.
A typical use of colcrt would be
tbl exum2.n | nroff -ms | colcrt – | more
The colcrt command appeared in 3.0BSD.
Should fold underlines onto blanks even with the ‘-’ option so that a
true underline character would show.
Cannot 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.
Characters that take up more than one column position may not be under‐
BSD July 31, 2004 BSD