Linux – How read mail from /var/spool/postfix/deferred

Here's a quick and dirty head start. No error checking, and it doesn't actually "move" anything as is.

#!/usr/local/bin/bash
#
# DIRTY hack to append all but the last 100 messages from each file
# in a dir of mbox files to like named files in /tmp
#
# if an mbox has less than 101 messages, skip it
#
# requires formail (from the procmail installation..)

#
# we're writing in tmp - to write in the user's dir move this 
# inside the for loop and use $USERMAIL to write the base path
DESTDIR="/tmp"

for USERMAIL in `ls -1`

do
MESSAGECOUNT=`cat $USERMAIL | formail -q -s wc | wc -l | sed 's/^[ \t]*//'`
COPYTHISMANY=`expr $MESSAGECOUNT - 100`
if [ $COPYTHISMANY -gt 0 ]
then
echo "Copying $COPYTHISMANY messages from $USERMAIL to /tmp/$USERMAIL.allbutlast100"
cat $USERMAIL | formail -$COPYTHISMANY -s cat >> $DESTDIR/$USERMAIL.allbutlast100
# copy the last 100 to a new file
cat $USERMAIL | formail +$COPYTHISMANY -s cat >> $DESTDIR/$USERMAIL.last100
# to replace the original source mbox do something like
# mv /tmp/$USERMAIL.last100 $USERMAIL
fi
done

If you ignore simple shell scripts almost every single programming language has a library to parse a mbox formated mailbox.

• http://docs.python.org/library/mailbox.html
• http://search.cpan.org/~dcoppit/Mail-Mbox-MessageParser-1.5002/lib/Mail/Mbox/MessageParser/Perl.pm
• http://www.phpclasses.org/browse/file/3127.html

Of course if you look around you can also find lots of POP3 and IMAP client libraries as well.

You should also be able to use something like procmail or maildrop to filter your messages.