It was suggested to me to use vacuum places to improve my Firefox awesome bar performance, as I’m still using Firefox 3.0 which is packaged with Jaunty; I do have 3.5 installed I just use it for testing sites at the moment. However realising that I didn’t need an addon a single line of bash will probably do what I want I headed to Google and found an explaining it all and a suitable one-liner to optimise all my Firefox SQLite DBs.
You will need the sqlite3 package installed and you should close Firefox prior to running the command.
for i in ~/.mozilla/firefox/*/*.sqlite; do echo "VACUUM;" | sqlite3 $i ; done
