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 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:
    MERGEWORDS=1 sh john.SlackBuild

For more information, consult the project's homepage and/or the documentation 
installed in /usr/doc/john-1.8.0