Compare sorted files FILE1 and FILE2 line by line.
With no options, produce three-column output. Column one contains
lines unique to FILE1, column two contains lines unique to FILE2,
and column three contains lines common to both files.
suppress lines unique to FILE1
suppress lines unique to FILE2
suppress lines that appear in both files
display this help and exit
output version information and exit
Written by Richard Stallman and David MacKenzie.
Report bugs to <email@example.com>.
Copyright 2006 Free Software Foundation, Inc.
This is free software. You may redistribute copies of it under the terms of
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
There is NO WARRANTY, to the extent permitted by law.
The full documentation for
is maintained as a Texinfo manual. If the
programs are properly installed at your site, the command