Useful git commands

git.sh

#make a new branch that tracks remote branche
git branch --set-upstream foo upstream/foo

#list the files modified on the last 10 commits and filter only spec files
git diff --name-only HEAD~10 | egrep _spec\.rb

#difference between the state of the file from 3 commits in the past
git diff HEAD~3 -- app/views/topics/merges/_new.html.haml

#run specs modified on the last 10 commits
spec `git diff --name-only HEAD~10 | egrep _spec\.rb`

#prune repos that where removed on remote
git remote prune origin