Man page 1 : colcrt

colcrt - filter nroff output for CRT previewing

.Op Fl .Op Fl 2 .Op Ar

The 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:

-tag -width indent
-Suppress all underlining. This option is especially useful for previewing .Em 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 as described in environ(7) .

.Ex -std

A typical use of would be

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

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

The command appeared in

x 3.0 .

Should fold underlines onto blanks even with the .Sq Fl option so that a true underline character would show.

Cannot back up more than 102 lines.

General overstriking is lost; as a special case .Ql | overstruck with .Ql - or underline becomes .Ql + .

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.