Using Procmail

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Using Procmail

• Charles Duan
• Harvard Univ. Computer Services
• March 27, 2002

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Using Procmail

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

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Using Procmail

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

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What is Procmail?

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

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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)

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Procmailrc Syntax
A basic .procmailrc
0 Header
From ksdavis_at_fas Patterns
Important-folder Action

0 Header
Subject \UA\ Patterns
lt 1024 Patterns
! my_at_email.com Action


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Delivering Mail with Procmail
Mail Received
Add to .inbox
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Using Procmail

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

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Basic Procmail Recipes

• Sorting Recipes
• Forwarding Recipes
• Program Recipes

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Sorting Recipes
Sorting
0
Subject \UA\ If Subject contains UA
uas-mail Put it in mailbox uas-mail

• Most common recipe used
• Multiple patterns accepted

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Forwarding Recipes
Forwarding
0 Header (no trailing colon)
From ksdavis If its from Kevin
! my_at_email.com Send it to my_at_email.com

• Multiple forwarding addresses accepted
• Multiple patterns accepted
• To keep a copy yourself, use 0c

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Program Recipes
Forwarding
0
Subject Survey If its for the survey
runstats.pl Run my program on it

• Used for processing online forms
• Very powerful proceed with caution
• Ill talk later about 0 v. 0

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Exercise
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Using Procmail

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

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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

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E-mail Structure Example
From cduan_at_fas... From line
From Aaron Lee ltlee42_at_... Header
To uas_at_fas.harvard.edu Header
Subject Interesting ... Header
Date Sun, 10 Feb 2002... Header
Blank line
I send you this file in Body
order to have your advice Body
I hope you can help me Body

• From line separates messages

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Regular Expressions

• Completely compatible with egrep
• By default, matches only header
• Watch out for spaces
• From cduan_at_fas Wrong
• From cduan_at_fas Right!
• (Thats a space and a tab in )

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Other Special Patterns

• ! Invert the pattern
• ? Run a program, use the exit code
• lt Under specified number of bytes
• gt Over specified number of bytes
• Evaluate quotes like /bin/sh

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Using Procmail

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

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Recipe Options

• Options placed after zero in header
• AaEe Run based on previous recipe
• f Change (filter) the mail
• c Continue through this recipe
• Read man procmailrc

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Another Exercise
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Using Procmail

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

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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 for forwarding, programs (?)

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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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The Last Blank Slide