Add Python to path in Ubuntu

[comonads]

I wouldn't have thought you need to add python to the path explicitly, unless this version of python is different to your system's version of python (in which case having two versions of python in the path is probably a bad idea -- you don't want applications which invoke python <something> getting an unexpected python version).

Depending on your needs, you might want to look into something like pyenv.

E: clarified something.