Crafty is a rapidly developing chess engine with more and more features
being added regularly.  It can play, analyze, and even annotate games
for you.  Crafty can utilize tablebases; these are available for FreeBSD
in the related ports.

The files bitmaps.tgz and sound.tgz are available in your doc directory,
usually /usr/local/share/doc/crafty.  The bitmaps are for html
annotations performed by crafty - they should be unpacked into the
directory you normally analyze games into, and all should be fine...

The sounds are for move announcements.  Unpack the archive somewhere,
and have a look at the 'speak' script to customize for your use, if
desired.

22.1 -> New "skill" command that can be used to "dumb down" crafty.
"skill <n>" where n is a number between 1 and 100.  100 is max (default)
skill.  Skill 70 will drop the playing Elo by about 200 points.  Skill
50 will drop it about 400 points.  The curve is not linear, and the
closer you get to 1, the lower the rating.