1.\" Copyright (c) 1980, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)colcrt.1 8.1 (Berkeley) 6/30/93 29.\" $FreeBSD: head/usr.bin/colcrt/colcrt.1 216370 2010-12-11 08:32:16Z joel $ 30.\" 31.Dd December 30, 2013 32.Dt COLCRT 1 33.Os 34.Sh NAME 35.Nm colcrt 36.Nd filter nroff output for CRT previewing 37.Sh SYNOPSIS 38.Nm 39.Op Fl 40.Op Fl \&2 41.Op Ar 42.Sh DESCRIPTION 43The 44.Nm 45utility provides virtual half-line and reverse line feed sequences 46for terminals without such capability, and on which overstriking 47is destructive. 48Half-line characters and underlining (changed to dashing `\-') 49are placed on new lines in between the normal output lines. 50.Pp 51The following options are available: 52.Bl -tag -width indent 53.It Fl 54Suppress all underlining. 55This option is especially useful for previewing 56.Em allboxed 57tables from 58.Xr tbl 1 . 59.It Fl 2 60Cause all half-lines to be printed, effectively double spacing the output. 61Normally, a minimal space output format is used which will suppress empty 62lines. 63The program never suppresses two consecutive empty lines, however. 64The 65.Fl 2 66option is useful for sending output to the line printer when the output 67contains superscripts and subscripts which would otherwise be invisible. 68.El 69.Sh ENVIRONMENT 70The 71.Ev LANG , LC_ALL 72and 73.Ev LC_CTYPE 74environment variables affect the execution of 75.Nm 76as described in 77.Xr environ 7 . 78.Sh EXIT STATUS 79.Ex -std 80.Sh EXAMPLES 81A typical use of 82.Nm 83would be 84.Bd -literal 85tbl exum2.n \&| nroff \-ms \&| colcrt \- \&| more 86.Ed 87.Sh SEE ALSO 88.Xr col 1 , 89.Xr more 1 , 90.Xr nroff 1 , 91.Xr troff 1 , 92.Xr ul 1 93.Sh HISTORY 94The 95.Nm 96command appeared in 97.Bx 3.0 . 98.Sh BUGS 99Should fold underlines onto blanks even with the 100.Sq Fl 101option so that 102a true underline character would show. 103.Pp 104Cannot back up more than 102 lines. 105.Pp 106General overstriking is lost; 107as a special case 108.Ql \&| 109overstruck with 110.Ql \- 111or underline becomes 112.Ql \&+ . 113.Pp 114Lines are trimmed to 132 characters. 115.Pp 116Some provision should be made for processing superscripts and subscripts 117in documents which are already double-spaced. 118.Pp 119Characters that take up more than one column position may not be 120underlined correctly. 121