Before you start - your search path

Regardless of which interpreter or compiler you plan on running, it's a good idea that its directory location is somewhere in your search path, so take the time to extend your PATH variable to include all of the relevant directories. The best place to do this is in your personal .bash_profile file.

Some suggestions (if they're not already in your search path) would be /usr/bin and /usr/local/bin, among others.