A simple shell script that checks firefox history against list of sites and deletes any matching entries. I compiled a list of all the pornsites I could think of. It may be useful to run this script as a cron job.
Requirements:
firefox
sqlite3
Instructions:
Change the value DBPATH to your places.sqlite file.
Usually located in /home/USER/.mozilla/firefox/USERID/places.sqlite
To add a custom site to the list, just make a new line in the hosts file