I am using Debian etch for production, plus Exim4 with per user ~/Maildir support. Since I hope to forward each user message to their own public email for backup, Procmail FAQ give me a useful example.
First of all, check if your Exim4 have ~/.procmailrc supported, which usually already there. Find the follow code snippet from /etc/exim4/exim4.conf.template:
#####################################################
### router/700_exim4-config_procmail
#####################################################
procmail:
debug_print = "R: procmail for $local_part@$domain"
driver = accept
domains = +local_domains
check_local_user
transport = procmail_pipe
# emulate OR with "if exists"-expansion
require_files = ${local_part}:\
${if exists{/etc/procmailrc}\
{/etc/procmailrc}{${home}/.procmailrc}}:\
+/usr/bin/procmail
no_verify
no_expn
#####################################################
### end router/700_exim4-config_procmail
#####################################################Work around together with Debian's procmail example (/usr/share/doc/procmail/examples/), just create a ~/.procmailrc as below:
# Please check if all the paths in PATH are reachable, remove the ones that
# are not.
PATH=$HOME/bin:/usr/bin:/usr/ucb:/bin:/usr/local/bin:.
MAILDIR=$HOME/Maildir/
DEFAULT=$MAILDIR
LOGFILE=$MAILDIR/from
LOCKFILE=$HOME/.lockmail
:0c
! someone@example.comSend an email to this user, check the mail log with tail -f -n 50 /var/log/exim4/mainlog and you will find that message already forward to your target public email address, with a saved local copy :-)
