A recent blog post on Planet Ubuntu reminded me of a trick to speed up Firefox (a little bit).

Firefox keeps a lot of temporary data (bookmarks, history,...) in SQLite databases. These database files require some cleanup every now and then. It turns out you can do this easily (for all your Firefox profiles) with one single command:

for i in ~/.mozilla/firefox/*/*.sqlite; do sqlite3 $i vacuum; done

You do have to close Firefox because otherwise you'll get a SQL error: database is locked.