The Linux file system In this article Hamish Taylor wants to explain the basics of the Linux file system and where you can expect to find things. (Read more) SpamAssassin SpamAssassin is a mail filter to identify spam using text analysis. Using its rule base, it uses a wide range of heuristic tests on mail headers and body text to identify "spam". SpamAssassin uses a wide variety of local and network tests to identify spam signatures. This makes it harder for spammers to identify one aspect which they can craft their messages to work around. Anti-spam tests and configuration are stored in plain text, making it easy to configure and add new rules. SpamAssassin encapsulates its logic in a well-designed, abstract API so it can be integrated anywhere in the email stream. The Mail::SpamAssassin classes can be used on a wide variety of email systems including procmail, sendmail, Postfix, qmail, and many others.