Sox and ecasound are incredibly useful too if you are into scripting.
I have made scripts to do things like "take this whole directory full of files and invert the right channel", or take this sample.wav and make me a bunch of different mid/side mixes at 30/70, 40/60, 50/50, 60/40, 70/30. Go get a cup off coffee, and when you come back it's done. If you were doing that in a GUI it would take you a half hour of tedious clicking.
By the way, I use Debian, which is the basis for Ubuntu. I should try Ubuntu, but I've been running Debian for years, and haven't had to build a new box from scratch in a while.