ShameMail takes an mbox-formatted file (mailbox or mailing list archive) and prints a list of all the senders, sorted by number of messages sent. It attempts to handle most common From: line formats and won't be bothered by users that change their name (though it cannot, of course, detect two different email addresses as the same person).
The final list is printed to stdout. Some chatter about combining of posters who change names is printed to stderr; if this bothers you try redirecting stdout to a file and reading the file.
To work correctly, Shamemail will need a "sort" program that acts the way sort does on a Red Hat Linux system.
Eric <e d s@ reric·net>