.\"-*- nroff -*-
.TH GDIFFMK 1 "7 November 2018" "Groff Version 1.22.3"
.SH NAME
.
.\" gdiffmk \- mark differences between groff/nroff/troff files
.
.
.\" --------------------------------------------------------------------
.\" Legal Terms
.\" --------------------------------------------------------------------
.
.de co
Copyright \[co] 2004-2014 Free Software Foundation, Inc.

This file is part of the gdiffmk utility, which is part of groff, a
free software project.

You can redistribute and/or modify gdiffmk under the terms of the GNU
General Public License as published by the Free Software Foundation,
either version 3 of the License, or (at your option) any later
version.

gdiffmk is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
..
.
.de au
This document was written and is maintained by
.MT MBianchi@Foveal.com
Mike Bianchi
.MT .
..
.
.\" --------------------------------------------------------------------
.SH SYNOPSIS
.\" --------------------------------------------------------------------
.
.nr a \n(.j
.ad l
.nr i \n(.i
.in +\w'\fBgdiffmk 'u
.ti \niu
.B gdiffmk
.de OP
.  ie \\n(.$-1 .RI "[\ \fB\\$1\fP" "\\$2" "\ ]"
.  el .RB "[\ " "\\$1" "\ ]"
..
.OP \-a \%addmark
.OP \-c \%changemark
.OP \-d \%deletemark
[\ \c
.B \-D
.OP \-B
.OP \-M "mark1 mark2"
]
.OP \-x \%diffcmd
.OP \-\-
.OP \-\-help
.OP \%\-\-version
.I \%file1
.I \%file2
[\ \c
.IR \%output \ \c
]
.br
.ad \na
.
.
.\" --------------------------------------------------------------------
.SH DESCRIPTION
.\" --------------------------------------------------------------------
.
.B gdiffmk
compares two
.BR groff (1),
.BR nroff (1),
or
.BR troff (1)
documents,
.I file1
and
.IR file2 ,
and creates an output which is
.I file2
with added `margin character' (.mc) commands that indicate the differences.
.
.
.LP
If the
.I output
filename is present,
the output is written there.
.
If it is
.B \-
or absent the output is written to the standard output.
.
.
.LP
If the
.I file1
or
.I file2
argument is
.B \-
the standard input is read for that input.
.
Clearly both cannot be
.BR \- .
.
.
.LP
Note that the output is not necessarily compatible with all macro packages
and all preprocessors.
.
See the
.B BUGS
section below.
.
.
.\" --------------------------------------------------------------------
.SH OPTIONS
.\" --------------------------------------------------------------------
.
.TP
.BI \-a addmark
Use the
.I addmark
for source lines not in
.I file1
but present in
.IR file2 .
.
Default:
.BR + .
.
.TP
.B \-B
By default, the deleted texts marked by the
.B \-D
option end
with an added troff break command,
.BR .br ,
to ensure that the deletions are marked properly.
.
This is the only way to guarantee that deletions and small
changes get flagged.
.
This option directs the program not to insert these breaks; it makes
no sense to use it without
.BR \-D .
.
.TP
.BI \-c changemark
Use the
.I changemark
for changed source lines.
.
Default:
.BR | .
.
.TP
.BI \-d deletemark
Use the
.I deletemark
for deleted source lines.
.
Default:
.BR * .
.
.TP
.B \-D
Show the deleted portions from changed and deleted text.
.
Default delimiting marks:
.BR "[[" " \&.\|.\|.\& " "]]" .
.
.TP
.BI \-M "mark1 mark2"
Change the delimiting marks for the
.B \-D
option.
.
It makes no sense to use this option without
.BR \-D .
.
.TP
.BI \-x diffcmd
Use the
.I diffcmd
command to perform the comparison of
.I file1
and
.IR file2 .
.
In particular,
.I diffcmd
should accept the GNU
.B diff
.BI \-D name
option.
.
Default:
.BR diff (1).
.
.TP
.B \-\-
All the following arguments are treated as file names,
even if they begin with
.BR \- .
.
.TP
.B \-\-help
Print a usage message on standard error output and exit.
.
.TP
.B \-\-version
Print version information on the standard output and exit.
.
.
.\" --------------------------------------------------------------------
.SH BUGS
.\" --------------------------------------------------------------------
.
The output is not necessarily compatible with all macro packages
and all preprocessors.
.
A workaround that is often successful against preprocessor problems is
to run
.B gdiffmk
on the output of all the preprocessors instead of the input source.
.
.
.LP
.B gdiffmk
relies on the
.BI \-D name
option of GNU
.BR diff (1)
to make a merged `#ifdef' output format.
.
It hasn't been tested whether other versions of
.BR diff (1)
do support this option.
.
See also the
.BI \-x diffcmd
option.
.
.
.LP
Report bugs to
.MT bug-groff@gnu.org
.ME .
.
Include a complete, self-contained example that will allow the bug to
be reproduced, and say which version of
.B gdiffmk
you are using.
.
.
.\" --------------------------------------------------------------------
.SH COPYRIGHT
.\" --------------------------------------------------------------------
.co
.\" --------------------------------------------------------------------
.SH AUTHORS
.\" --------------------------------------------------------------------
.au
.
.
.\" --------------------------------------------------------------------
.SH "SEE ALSO"
.\" --------------------------------------------------------------------
.
.BR groff (1),
.BR nroff (1),
.BR gtroff (1),
.BR diff (1)
.
.\" Local Variables:
.\" mode: nroff
.\" End: