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
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.