John the Ripper is a fast password cracker.  Its primary purpose is to detect 
weak passwords.  Besides several crypt(3) password hash types most commonly 
found on various Unix flavors, supported out of the box are Kerberos AFS and 
Windows NT/2000/XP/2003 LM hashes, plus several more with contributed patches.

This script includes an option to apply the community-enhanced "Jumbo" patch, 
which integrates lots of contributed patches adding support for over 40
additional hash and cipher types (including popular ones such as NTLM, raw MD5,
etc.), as well as some optimizations and features. Unfortunately, its overall
quality is lower than the official version's.  To include the Jumbo patch, 
simply pass JUMBO=1 to the build script:
    JUMBO=1 sh john.SlackBuild

This script also includes an option to merge the /usr/share/dict/words 
dictionary into the standard password list, which marginally improves results
compared with the default password list.  To include this, simply pass
MERGEWORDS=1 to the build script:
    MERGEWORDS=1 sh john.SlackBuild

The options can be used in combination as well:
    JUMBO=1 MERGEWORDS=1 sh john.SlackBuild

For more information, consult the documentation installed in:
    /usr/doc/john-1.7.8
and, of course, the John the Ripper homepage:
    http://www.openwall.com/john