Is it possible to run selenium (Firefox) web driver without a GUI?

We are considering upgrading our production server from Ubuntu-**desktop** 10.04 to Ubuntu-**server** 12.04. We have various services running on our current desktop OS such as Selenium Web Driver. My question is can the Selenium Web Driver be run from a cli-based system? My immediate thought is that it can't, because it relies on Firefox, but I'd like for someone to prove me wrong!