Setup on Debian for use with EXIM.

apt-get install spamassassin sa-compile

Edit /etc/spamassassin/local.cf to add local rules.

Compiling rules will speed up spamd but it will work otherwise.

compile-spamd.sh

#! /bin/sh
sa-compile
chown -R debian-spamd:debian-spamd /var/lib/spamassassin
chmod -R go-w,go+rX /var/lib/spamassassin/compiled
kill -HUP `cat /var/run/spamd.pid`
exit 0

Run from cron once per day, week or month.

#! /bin/sh
sa-update --nogpg
compile-spamd.sh
exit 0

#! /bin/sh
export TZ="UTC"
rm -f /var/run/spamd.pid
exec /usr/sbin/spamd --helper-home-dir=/var/lib/spamassassin --create-prefs --nouser-config -udebian-spamd -gdebian-spamd --socketpath=/var/run/spamd.sock --socketowner=debian-spamd --socketgroup=debian-spamd --socketmode=0777 --max-children 5 --pidfile /var/run/spamd.pid