this is obsolete doc -- see http://doc.nethence.com/ instead

Configuring the procmail Mail Delivery Agent 

http://pbraun.nethence.com/unix/mail/procmail.html 

http://pbraun.nethence.com/unix/mail/procmail-bmf.html 

http://pbraun.nethence.com/unix/mail/procmail-qsf.html 

Introduction (update) 

It is a good idea to use the Maildir format instead of traditional mbox. It allows several imap connections to read and write to the folders at the same time. Also, it's faster than mbox as each email is stored in a seperate file (mbox need to read the whole file to show the messages in a folder...). Finally, it still creates folders that does not exist, even sub-sub folders (subfolder are in the .sub.folder layout anyway), just like with traditionnal procmail rules. 

To use Maildir, use e.g. this as destination (note the dot prefix and the trailing slash) 

.folder/

and for subfolders, 

.folder.sub/

and for the INBOX and default folder, 

ORGMAIL=$HOME/Maildir/

MAILDIR=$HOME/Maildir

DEFAULT=$ORGMAIL

Requirements 

Make sure procmail is installed on your system, 

which procmail

System configuration 

There are basically three ways for using procmail : 

- As an SMTP daemon MDA 

If you're getting messages from your smtp daemon, 

vi ~/.forward

like, 

"|IFS=' '&&p=/usr/local/bin/procmail&&test -f $p&&exec $p -f-||exit 75"

Ref. http://mirror.ncsa.illinois.edu/procmail-faq/mini-faq.html#forward 

- As a POP receiver MDA 

If you're getting message for several POP accounts, it's preferable to make a clean cut separation between the procmail configs and call procmail with -m (with fetchmail or getmail). 

- Manually or by some script 

For example, see the "Reprocessing messages" chapter below. 

procmail rules examples 

Here are some procmail configuration examples, 

cd ~/

wget http://pbraun.nethence.com/configs/mail/.procmailrc

wget http://pbraun.nethence.com/configs/mail/.procmailrc.trash

Refs. 

11.6 Matching last Received header: http://www.hcs.harvard.edu/~thurston/ua/pm-tips.html#matching_last_received_header 

Note. yes, SHELL=/bin/ksh permits to use the KSH syntax e.g., 

* ? [[ -f lists/file1 || -f lists/file2 ]]

and 

* !? [[ -f lists/file1 || -f lists/file2 ]]

Note. DO NOT use the signature dashes wiper, it breaks attached PDF documents, 

# DO NOT USE : THIS BRAKES PDF ATTACHMENTS

# Fix signature dashes

#:0 fBw

#* ^--$

#| sed -e 's/^--$/-- /'

Note. To backup incoming messages by date, 

yearmonth=`date +%Y%m`

:0 c

backup.$yearmonth

Using Maildir format 

Note. no colon after :0 on Maildir folders, and the trailing slash (/) is mandatory. 

Note. Maildir folder based on dots is better than filesystem based because you do not have to care about the folder existing or not, when writing a procmail rule, 

:0

* ^From:.*(Charlie Root|Cron Daemon|logwatch@)

.archives.$YEAR.crontabs/

will just create the folder in case it doesn't exist (which is a file, that is the point). 

Rewrite subject with formail 

One-liner to change the subject header, 

        :0 fh

        * Subject: \/.*

        | formail -I "Subject: [some text] $MATCH"

But if you already need the MATCH variable for something, you can also use a seperate rule to isolete a 'subject' variable, 

        :0 chfw

        subject=| /usr/bin/formail -xSubject:

        :0 Hf

        | /usr/bin/formail -i "Subject: [$MATCH] $subject"

Note. 'chfw' to forge a variable out of some header 

Note. 'Hf' to pipe the message to formail 

Clean-cut POP accounts separation 

You may use condition checks against the Received header, 

:0

* ^Received:.*IP_OR_HOSTNAME

{

Note. for that, enable your POP fetcher's ability to add its own Received header 

Misc syntax tips 

Note. exclude some messages e.g. messages having a spam-like Reply-To, 

* !^Reply-To:.*@spamdomaine.com

Note. ':0 Wic' for piping to mkdir (man procmailex) 

Note. ':0E' for procmail 'else if' condition 

Other procmail configuration examples: 

http://spacepants.org/conf/dot.procmailrc 

http://puzzling.org/computing/help/procmail 

http://bethesignal.org/dotfiles/procmailrc.html 

Reprocessing messages (mbox and Maildir) 

Installation 

As the username which has the .procmailrc file and which will use it, add ~/bin to its path and fetch the reprocess script, 

cd ~/

mkdir -p bin/

cd bin/

wget http://www.uq.edu.au/~suter/software/reprocess-mbox-via-procmail/reprocess-mbox-via-procmail

chmod +x reprocess-mbox-via-procmail

Note. formaly found on http://zwitterion.org/software/reprocess-mbox-via-procmail/. 

Also provide a wrapper for Maildir folders, 

vi reprocess_maildir

like, 

#!/bin/ksh

#

# Re-process a Maildir format mailbox with Procmail

#

set -e

[[ -z $1 ]] && print \$1 missing && exit 1

[[ ! -d $1 ]] && print folder $1 does not exist && exit 1

[[ ! -r $1 ]] && print folder $1 is not readable && exit 1

find $1/cur $1/new -type f | while read msg; do

        print Processing $msg...\\c

        procmail < $msg && rm -f $msg && print Done

done

Configuration 

Eventually adapt the called procmailrc file accordingly, 

vi reprocess-mbox-via-procmail

change, 

formail -s procmail -m /PATH/TO/.procmailrc < $tmpfile || die $0: formail failed - data in $tmpfile.

On NetBSD, you'll also have to make sure those packages are installed (not the base system mktemp, we need the sysutils/mktemp one), 

pkg_info | grep bash

pkg_info | grep mktemp

and fix the script, 

cd ~/bin/

vi reprocess-mbox-via-procmail

change '#!/bin/bash' and add /usr/pkg/{bin,sbin} to the PATH declaration. 

Usage 

As the username which has access to the .procmailrc, reprocess an mbox like, 

cd /var/spool/virtual/example.net/user.imap/

reprocess-mbox-via-procmail MBOX_FILENAME

Alternatives 

Use 'formail -s' to split the messages, 

formail -ds procmail -Y -m $HOME/.procmailrc < mbox.input

Note. eventually use '-d' to handle non-standard message formats 

Note. -d and -Y to deal with traditionnal mail format. Otherwise you may get thousands of times the same email, or just one email for the whole mbox. 

Or simply resend the messages through sendmail/procmail, 

cat mbox | usr/sbin/sendmail -oi user@example.com

Removing duplicates from an mbox 

Get the perl script from [Bill's webpage hacks] (http://wdr1.com/hacks/) to remove duplicates. Be careful, it's in DOS format! Convert with e.g. dos2unix. 

mkdir -p ~/bin/

cd ~/bin/

#wget http://wdr1.com/projects/mbox-dedup.pl

wget http://pbraun.nethence.com/scripts/mail/mbox-dedup.pl

dos2unix mbox-dedup.pl

chmod +x mbox-dedup.pl

Note. eventually fix the perl path (using NetBSD?...), 

#vi mbox-dedup.pl

Note. Many thanks to [William Reardon] (http://wdr1.com/) for this script. 

Remove duplicates, 

cd /var/spool/virtual/example.net/user.imap/

#mbox-dedup.pl --help

mbox-dedup.pl mbox

rm -f mbox.bak

Otherwise, directly within the procmail rules, 

:0 Wh: msgid.lock

| /usr/bin/formail -D 8192 /var/log/mailuser/msgid-noduplicate.cache

Troubbleshooting 

Note. I didn't had much success with that one, 

:0 Wh: msgid.lock

| /usr/bin/formail -D 8192 /var/log/mailuser/msgid.cache

References 

http://userpages.umbc.edu/~ian/procmail.html 

http://partmaps.org/era/procmail/mini-faq.html 

http://lipas.uwasa.fi/~ts/info/proctips.html#orrules 

http://pm-doc.sourceforge.net/doc/ 

http://sial.org/howto/procmail/ 

Great guide : http://partmaps.org/era/procmail/quickref.html 

Sweet regex manual : http://www.perlcode.org/tutorials/procmail/regular_expressions.pod 

Some mail headers : http://people.dsv.su.se/~jpalme/ietf/mail-headers/mail-headers.txt 

Gentoo procmail : http://gentoo-wiki.com/Procmail_configuration 

Timo's procmail tips and recipes : http://lipas.uwasa.fi/~ts/info/proctips.html 

http://lists.debian.org/debian-user/2001/12/msg02530.html 

http://luv.asn.au/overheads/procmail.html 

http://tldp.org/LDP/LG/issue14/procmail.html