Tag: Procmail

Delaying Email Delivery Using Procmail and Cron

Because I use Mutt, any mailbox that has new mail tends to get my attention when I check my email. This became particularly annoying because I kept opening my spam mailbox to check a single spam message. Therefore, I decided to come up with a way to delay the delivery of my spam to once per day.

I started by changing my “.procmailrc” to deliver spam messages to a different mailbox that Mutt does not check.

MAIL=`echo $HOME/Mail`
[...]
:H
* ^X-Spam-Status: Yes
$MAIL/delay_spam
[...]

Then I created a new procmailrc file called “spam.procmailrc” that would deliver mail to my checked spam mailbox.

MAIL=`echo $HOME/Mail`

:0
$MAIL/spam

Next, I wrote a short Bash script to use Formail and Procmail to deliver all of the messages in the delayed delivery spam mailbox to the normal spam mailbox.

#! /bin/bash

FORMAIL=/usr/bin/formail
PROCMAIL=/usr/bin/procmail
PROCMAILRC=$HOME/.procmail/spam.procmailrc

MAIL=$HOME/Mail
DELAY=$MAIL/delay_spam
TEMP=$MAIL/.spam
LOCK=$TEMP.lock

# Make sure there is delayed mail and we can get the lock (retry once)
if ( test -s $DELAY && lockfile -r 1 $LOCK 2>/dev/null ); then

    # Add the delayed mail to the temp mailbox and empty the delayed mailbox
    cat $DELAY >> $TEMP && cat /dev/null > $DELAY
    # Process each delayed message
    $FORMAIL -s $PROCMAIL $PROCMAILRC < $TEMP && rm -f $TEMP

    # Delete the lock now that we are done
    rm -f $LOCK
fi

Finally, I set the script to run daily using Cron. Now I am only interrupted by spam when I choose to be instead of every time a new message arrives. I have used the same technique to delay the delivery of emails to unimportant mailing lists so I only read them hourly instead of every time a message arrives.

Extract Email Attachments With Procmail and Munpack

I regularly use the Marquette University PrintWise Canon copiers to scan paper documents into PDF files. These files are delivered to me via email where I manually save each PDF attachment, rename it, and move it to the appropriate directory. Using Procmail and Munpack, I was able to eliminate some of the tedium of this problem.

I inserted the following block of code into my .procmailrc file. It looks for emails that were sent from me and to me by a Canon copier. When it finds one, it copes the email and pipes it to Munpack which extracts the attachments into my attachments directory.

ATTACH=`echo $HOME/attachments`
:0 c
* ^To:.*[email protected]
* ^From:.*[email protected]
* ^X-Mailer: Canon imageRUNNER
| munpack -q -C $ATTACH

After the attachment has been extracted, I can rename it and move it to the appropriate directory, and I still receive the email in my inbox so I know I have attachments to deal with.

Bayes Filtering in SpamAssassin

The Bayesian classifier in SpamAssassin began tagging emails a few days ago. I found this out because while messages were not marked as spam, my procmail rule started diverting all messages to my spam folder. The old rule was not particular about where the yes was and since BAYES contains yes, all emails looked like spam. The new rule only looks for the yes at the beginning.

# Old Rule
:H
* ^X-Spam-Status:.*Yes
$MAIL/spam
# New Rule
:H
* ^X-Spam-Status: Yes
$MAIL/spam

Now incoming spam messages contain an additional score in the spam report.

X-Spam-Report:
        *  3.5 BAYES_99 BODY: Bayesian spam probability is 99 to 100%
        *      [score: 1.0000]

I was surprised that it took the Bayes filter three months to gather enough email to begin scoring incoming email. It is a nice addition because it bumps up the spam scores enough to ensure that more messages that are spam get marked as such.