NAME
colcrt - filter nroff output for CRT previewing

SYNOPSIS
colcrt [ - ] [ -2 ] [ file ... ]

DESCRIPTION
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.

The optional - suppresses all underlining. It is especially useful
for previewing allboxed tables from tbl(1).

The option -2 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
invisible.

A typical use of colcrt would be

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

SEE ALSO
nroff(1), troff(1), col(1), more(1), ul(1)*

BUGS
Should fold underlines onto blanks even with the ‘-’ option so that
a true underline character would show; if we did this, however,
colcrt wouldn’t get rid of cu’d underlining completely.

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.

__________
* Not currently supported under MachTen