Rule Variables
..............

   Gnus uses "rule variables" to decide how to view a file.  All these
variables are on the form

           (list '(regexp1 command2)
                 '(regexp2 command2)
                 ...)

`gnus-uu-user-view-rules'
     This variable is consulted first when viewing files.  If you wish
     to use, for instance, `sox' to convert an `.au' sound file, you
     could say something like:
                 (setq gnus-uu-user-view-rules
                   (list '(\"\\\\.au$\" \"sox %s -t .aiff > /dev/audio\")))

`gnus-uu-user-view-rules-end'
     This variable is consulted if Gnus couldn't make any matches from
     the user and default view rules.

`gnus-uu-user-archive-rules'
     This variable can be used to say what commands should be used to
     unpack archives.