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OpenBSD: Using Procmail and Mutt to filter mailing lists

In this tutorial we'll see how to use filters to filter (d'oh) mails coming from various mailing lists. Have you ever thought about not subcribing to mailing lists because it would flood your INBOX? Here is one of the solutions available. Enjoy!

Software versions used

Installing and configuring Procmail

First of all, what is Procmail? Procmail can be used to create mail-servers, mailing lists, sort your incoming mail into separate folders/files, preprocess your mail, start any programs upon mail arrival or selectively forward certain incoming mail automatically to someone.

Let's install it now: change directory to the procmail location in the ports tree, build and install it:

# cd /usr/ports/mail/procmail
# make install clean

NOTE: if you do not have enough diskspace to install from the ports tree, use the pkg_add(1) way.

Now that procmail is installed, let's configure it to suit our needs.

Create a configuration file in your home directory. Note that your home directory should have the execute/search bit (o+x) set and .procmailrc should be world readable (o+r):

$ $EDITOR ~/.procmailrc

NOTE: the $EDITOR variable must be set to your favorite text editor. For instance, export EDITOR=vi for Bourne Shells users and setenv EDITOR vi for C Shells users.

Now edit it with the following content: 

VERBOSE=off

# Mutt and Elm use 'Mail'; Pine uses 'mail'
MAILDIR=$HOME/Mail/

# Directory for storing procmail log and rc files
PMDIR=$HOME/.procmail   # or $HOME/.Procmail for easier TAB-completion

LOGFILE=$PMDIR/log
INCLUDERC=$PMDIR/rc.lists

Now we got our own configuration file, let's see about our rc.lists file that will contain the actions we want procmail to take when we receive a mail that matches one of our rules:

$ $EDITOR ~/.procmail/rc.lists

As a first example, we will redirect mails sent by owner-misc@OpenBSD.org to the ~/Mail/IN.OpenBSD-misc mailbox. Mails that do not match this rule are still delivered to the user's default mailbox (/var/mail/$LOGNAME).

:0
* ^Sender:.*owner-misc@OpenBSD.org
IN.OpenBSD-misc

You can, of course, do the same for the any other OpenBSD.org mailing list.

Installing and configuring mutt

You might already be accustomed to installing OpenBSD ports or packages so we'll do it quick: 

# cd /usr/ports/mail/mutt
# make install clean
Once you got Mutt installed, get you a default dot-muttrc configuration and let's start editing it so Mutt will inform you when new mails have arrived in your different mailboxes.

$ $EDITOR ~/.muttrc

NOTE: ~/.mutt/muttrc is also a valid location for the configuration file.

and add the following into it: 

mailboxes ! =IN.OpenBSD-misc =IN.OpenBSD-tech =IN.OpenBSD-ports \
            =IN.OpenBSD-sources-changes =IN.OpenBSD-hppa =IN.OpenBSD-sparc

This way, Mutt will notify you when new mails have arrived in the above mailboxes. When starting Mutt, you'll see the following message in the bottom of your screen:

- Mutt 1.4i [2] (moo:/var/mail/xsa) 2 more to go.

Now press the c key and Mutt will ask you if you want to open the mailbox IN.OpenBSD-misc (assuming new mails have entered this mailbox).

Open mailbox ('?' for list): =IN.OpenBSD-misc

press Enter and it will proceed it. If you want to have a look at the other filled mailboxes, just press the c key again and repeat the operation.

Quick Sendmail configuration

By default, /etc/mail/localhost.cf and /etc/mail/sendmail.cf do not have the Procmail feature enabled. To do so we'll have to do a quick hack in the configuration file located in /usr/share/sendmail/cf/openbsd-localhost.mc then rebuild the localhost.cf we use:

# cd /usr/share/sendmail/cf
# $EDITOR openbsd-localhost.mc

In this file, add:

FEATURE(local_procmail)

and replace:

MAILER(local)dnl

by

MAILER(procmail)dnl

Now generate a new localhost.mc with the following commands (assuming you are still in /usr/share/sendmail/cf/):

# m4 ../m4/cf.m4 openbsd-localhost.mc > localhost.cf

Then backup your existing configuration, replace it with the new one and restart Sendmail:

# cp /etc/mail/localhost.cf /etc/mail/localhost.cf.orig
# cp localhost.cf /etc/mail/localhost.cf
# kill -HUP $(head -n1 /var/run/sendmail.pid)

Now you have finished with the various configurations, subscribe to the OpenBSD.org mailing lists and give it a try :-)

Published on May 21, 2003 on open.bsdcow.net