How to filter git diff based on file extensions?

Question

Is there an option to restrict git diff to a given set of file extensions?

Answer 1

None of the answers above seem to work for me under git bash on Windows. I am not sure if it is a version thing (I'm using 1.8.4) or Windows/bash thing; also, in my case, I wanted to diff two branches where each branch had additional files not present in the other branch (thus the 'find' based ones are remiss).

Anyway this worked for me (in my example, looking for a diff between python files):

git diff branch1 branch2 -- `git diff --summary branch1 branch2 | egrep '\.py$' | cut -d ' ' -f 5`