The pipe.pl script provides a way to have POPFile classify messages piped to it by other processes that
can then take the classified message and deal with it.
It accepts the raw message text (you should include headers) on stdin. Then classifies the message and
inserts the POPFile X-Text-Classification and/or performs Subject line modification as configured in
POPFile. It finally emits the now classified message (including new header and modified Subject line) on
stdout.
You should run this script as user and group popfile to avoid permission problems with the data used by
the daemon.