Chapter 15. Email

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Many environment variables are not used by most Procmail users, and many of the more important

environment variables are already defined a default value. Most of the time, you will be dealing with

the following variables:

  DEFAULT

  Sets the default mailbox where messages that do not match any recipes will be placed.

The default

DEFAULT

value is the same as

$ORGMAIL

.

  INCLUDERC

  Specifies additional

rc

files containing more recipes for messages to be checked

against. This allows you to break up your Procmail recipe lists into individual files that fulfill

different roles, such as blocking spam and managing email lists, that can then be turned off or on

by using comment characters in the user's

.procmailrc

file.

For example, two lines in a user's

.procmailrc

file may look like this:

MAILDIR=$HOME/Msgs

INCLUDERC=$MAILDIR/lists.rc

INCLUDERC=$MAILDIR/spam.rc

If the user would like to turn off the Procmail filtering of their email lists but leave spam control in

place, they could simple comment out the first

INCLUDERC

line with a

#

character.

  LOCKSLEEP

  Sets the amount of time, in seconds, between attempts by Procmail to use a partic 

ular lockfile. The default is eight seconds.

  LOCKTIMEOUT

  Sets the amount of time, in seconds, that must pass after a lockfile was last

modified before Procmail will assume that the lockfile is simply old and can be deleted. The default

is 1024 seconds.

  LOGFILE

  The location and file to contain any Procmail informational or error messages.

  MAILDIR

  Sets the current working directory for Procmail. If set, all other Procmail paths are

relative to this directory.

  ORGMAIL

  Specifies the original mailbox, or another place to put the messages if they cannot be

placed in the default or recipe required location.

By default, a value of

/var/spool/mail/$LOGNAME

is used.

  SUSPEND

  Sets the amount of time, in seconds, that Procmail will pause if a necessary resource,

such as swap space, is not available.

  SWITCHRC

  Allows a user to specify an external file containing additional Procmail recipes,

much like the

INCLUDERC

option, except that recipe checking is actually stopped on the referring

configuration file and only the recipes on the

SWITCHRC

 specified file are used.

  VERBOSE

  Causes Procmail to log much more information. This option is useful for debugging.

Other important environmental variables are pulled from your shell, such as

LOGNAME

, which is your

login name,

HOME

, which is the location of your home directory, and

SHELL

, which is your default

shell.

A comprehensive explanation of all environments variables, as well as their default values, is available

on the

procmailrc

man page.

15.5.2. Procmail Recipes

New users often find the construction of recipes the most difficult part of learning to use Procmail. To

some extent, this is understandable, as recipes do their message matching using regular expressions,

which is a particular format used to specify qualifications for a matching string. However, regular

expressions are not very difficult to construct and even less difficult to understand when read. Addi 

tionally, the consistency of the way Procmail recipes are written, regardless of regular expressions,

makes it easy to figure out what is going on.