.\" Copyright (c) 1980 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms are permitted
.\" provided that the above copyright notice and this paragraph are
.\" duplicated in all such forms and that any documentation,
.\" advertising materials, and other materials related to such
.\" distribution and use acknowledge that the software was developed
.\" by the University of California, Berkeley.  The name of the
.\" University may not be used to endorse or promote products derived
.\" from this software without specific prior written permission.
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
.\" WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
.\"
.\"	@(#)colcrt.1	6.3 (Berkeley) %G%
.\"
.TH COLCRT 1 ""
.UC
.SH NAME
colcrt \- filter nroff output for CRT previewing
.SH SYNOPSIS
.B colcrt
[
.B \-
] [
.B \-2
] [
file ...
]
.SH DESCRIPTION
.I 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.
.PP
The optional
.B \- 
suppresses all underlining.
It is especially useful for previewing
.I allboxed
tables from
.IR  tbl (1).
.PP
The option
.B \-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
.B \-2
option is useful for sending output to the line printer when the output
contains superscripts and subscripts which would otherwise be invisible.
.PP
A typical use of
.I colcrt
would be
.PP
.DT
	tbl exum2.n | nroff \-ms | colcrt \- | more
.SH "SEE ALSO"
nroff/troff(1), col(1), more(1), ul(1)
.SH BUGS
Should fold underlines onto blanks even with the
`\fB\-\fR'
option so that
a true underline character would show; if we did this, however,
.I colcrt
wouldn't get rid of
.I cu'd
underlining
completely.
.PP
Can't back up more than 102 lines.
.PP
General overstriking is lost;
as a special case `|' overstruck with `\-' or underline becomes `+'.
.PP
Lines are trimmed to 132 characters.
.PP
Some provision should be made for processing superscripts and subscripts
in documents which are already double-spaced.