Using Procmail Charles Duan Harvard Univ Computer Services

Using Procmail Charles Duan Harvard Univ. Computer Services March 27, 2002

Using Procmail • What is procmail? • Basic procmailrc recipes • Using patterns • Recipe options • File locking

Using Procmail • What is procmail? • Basic procmailrc recipes • Using patterns • Recipe options • File locking

What is Procmail? • Procmail is a processor of e-mail • Filter mail by headers/content • Multiple delivery possibilities – Mailboxes – Forwarding Addresses – Programs

Procmail Recipes • Procmail filters e-mails based on recipes in the. procmailrc file • Recipes contain: – What kind of e-mail the recipe handles – What to do with the e-mail • At most one recipe executes (unless otherwise specified)

Procmailrc Syntax # A basic. procmailrc : 0: * ^From: ksdavis@fas Important-folder : 0: * ^Subject: *[UA] * < 1024 ! my@email. com Header Patterns Action

Delivering Mail with Procmail Mail Received Run. procmailrc Add to. inbox No more recipes Read a “recipe” Match No match Execute action

Using Procmail • What is procmail? • Basic procmailrc recipes • Using patterns • Recipe options • File locking

Basic Procmail Recipes • Sorting Recipes • Forwarding Recipes • Program Recipes

Sorting Recipes # Sorting : 0: * ^Subject: *[UA] uas-mail If Subject contains “[UA]” Put it in mailbox “uas-mail” • Most common recipe used • Multiple patterns accepted

Forwarding Recipes # Forwarding : 0 * ^From: *ksdavis ! my@email. com Header (no trailing colon) If it’s from Kevin Send it to “my@email. com” • Multiple forwarding addresses accepted • Multiple patterns accepted • To keep a copy yourself, use “: 0 c”

Program Recipes # Forwarding : 0 * ^Subject: *Survey | runstats. pl If it’s for the survey Run my program on it • Used for processing online forms • Very powerful; proceed with caution • I’ll talk later about “: 0: ” v. “: 0”

Exercise

Using Procmail • What is procmail? • Basic procmailrc recipes • Using patterns • Recipe options • File locking

E-mail Structure • Two parts: header and body • Separated by an empty line • Each line of header is “Field: Value” – Special “From” line • Based on Berkeley mbox format

E-mail Structure Example From cduan@fas. . . From: Aaron Lee <lee 42@. . . To: uas@fas. harvard. edu Subject: Interesting. . . Date: Sun, 10 Feb 2002. . . “From” line Header Blank line I send you this file in order to have your advice I hope you can help me Body • “From” line separates messages

Regular Expressions • “Completely” compatible with egrep • By default, matches only header • Watch out for spaces – * From: cduan@fas Wrong – * From: [ ]*cduan@fas Right! – (That’s a space and a tab in [ ])

Other Special Patterns • ! Invert the pattern • ? Run a program, use the exit code • < Under specified number of bytes • > Over specified number of bytes • $ Evaluate quotes like /bin/sh

Using Procmail • What is procmail? • Basic procmailrc recipes • Using patterns • Recipe options • File locking

Recipe Options • Options placed after zero in header • Aa. Ee: Run based on previous recipe • f: Change (filter) the mail • c: Continue through this recipe • Read “man procmailrc”

Another Exercise

Using Procmail • What is procmail? • Basic procmailrc recipes • Using patterns • Recipe options • File locking

File Locking • Prevents procmail processes from corrupting mailboxes • Locking type depends on header – : 0 No locking – : 0: Default lock – : 0: lock Lock the file lock • Not forwarding, programs (? )

Hints and Tips • Test your recipes before using them • Resources for more information – man procmail, procmailrc, procmailex – www. procmail. org • Have fun using procmail!

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