| spamassassin -P
I should point out that you'll probably want to setup a backup mechanism until you are sure that everything is working properly, perhaps by copying all incoming mail to a backup folder before performing any changes. The above will cause all mail to pass through SpamAssassin as a filter and continue on throughout the remainder of your procmail recipes.
By default, SpamAssassin will perform a good number of tests on your messages and produce a "spam score" for each message. Simple tests such as a lack of a sender name or email addresses with the username portion ending in numbers receive a lower score, while larger indicators such as no MX record for the sending domain or known spam-harboring relays being used receive appropriately-weighted scores. All of this is configurable, but you'll probably find the defaults to be acceptable. SpamAssassin by default will treat anything with a score of five or more as spam and will modify the subject line, insert some notes into the body, and possibly even modify the Content-Type in the case of potentially harmful HTML mail. All messages receive a scoring header, even if they don't meet the spam requirement.
At this point, you could be finished and could just use the warning signs to skip over potential spam. However, I have gone a few steps further. Adding a procmail recipe such as this will filter tagged spam into a "junk" folder:
* ^X-Spam-Flag: YES
The above is a header that is added by SpamAssassin for mail that meets the threshold (in addition to the subject modifications and other headers).
1. One nice trick is a hook for the junk folder that sets everything to delete by default. A quick glance of the headers, and closing the mailbox deletes the messages forever:
folder-hook junk push 'D.\n'
Of course you could always view and/or copy any of the messages in this folder before leaving if you want to save the message (see tip #3 below for how to remove SpamAssassin's markup from messages you'd like to keep).
2. Another trick is a combination of configurations that allows you to both see whether something is listed in Vipul's Razor, (one of the tests used in SpamAssassin) and to report it to Razor if it is not. To let you know if it's already reported:
message-hook "~h RAZOR" "unignore X-Spam-Status"
If it's not reported (and you choose to), you may easily report the mail with the keystroke S if you use this:
macro index S "| spamassassin -r" "report message to Vipul's Razor"
3. This last trick is useful if you use vi/vim as your Mutt editor. If a message is accidentally tagged as spam and you would like to keep it, you can hit e to edit the message and in vim type :%!spamassassin -d to remove all SpamAssassin markup from the message. Then, just quit out of vim and your new message will have replaced the old one in the folder.
$Id: spamtricks.html,v 1.3 2002/03/04 00:51:36 incanus Exp $