Clone git submodules

Cloning a git repo only to find that the code won't build because of dependencies in un-cloned submodules is pretty annoying. To solve this clone the repo like so:

git clone --recursive git://github.com/foo/bar.git

This will also clone all the submodules associated with the parent repo.

Or if the git repo is already cloned:

git submodule init 
git submodule update