Provided by: bsdmainutils_11.1.2ubuntu2_amd64
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 overstriking 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(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.
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 underlined correctly.