COLCRT(1)
BSD General Commands Manual
COLCRT(1)
NAME
colcrt — filter nroff output for CRT previewing
SYNOPSIS
colcrt [ − ] [ −2] [file ...]
DESCRIPTION
The colcrt utility 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 dash-
ing ‘−’) 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(1).
−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.
ENVIRONMENT
The LANG, LC_ALL and LC_CTYPE environment variables affect the execution of colcrt as described in
environ(7).
EXIT STATUS
The colcrt utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
A typical use of colcrt would be
tbl exum2.n | nroff −ms | colcrt − | more
SEE ALSO
col(1), more(1), nroff(1), troff(1), ul(1)
HISTORY
The colcrt command appeared in 3.0BSD.
BUGS
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 underlined correctly.
BSD
July 31, 2004
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