Hm my Ubuntu education is coming to an end? Or is it? I think I am hooked...
This implies your relatively new to building source on Ubuntu. If not, forgive me if this sounds condescending.
An easy way to quickly build is to just copy/paste the instructions in the BUILD_UBUNTU.md. The trick is to open a shell then do sudo vi first so that you can enter your password and the cut and paste will go smoothly when it hits the sudo commands. Otherwise it'll stop and ask you because it's likely the sudo permission has timed out.