procmail is a mail processor which can do a variety of things with and/or in response to your mail. It can selectively sort, forward, reject, remail or allow your mail to be delivered to you in the normal fashion.
Before you start using it, you should at least look at the manpage for procmail.
procmail is invoked on newly received mail via the .forward file. The contents of .forward should be
"|IFS=' ';exec /usr/local/bin/procmail #YOUR_LOGIN_NAME"where YOUR_LOGIN_NAME is your user ID.
procmail determines what to do based on "recipes" found in the .procmailrc file.
: * ^From: .*firstname.lastname@example.org /dev/nullThe first line (":") starts the recipe. The second is an egrep regular expression to search the incoming message for. The third tells where to deliver the message if the above expression is matched. (/dev/null is the "bit bucket.")