No master commit, son. (Source: http://dev.chromium.org/developers/how-tos/get-the-code)

pre-commit

#!/bin/bash

# Prevent commits against the 'master' branch
if [[ `git rev-parse --abbrev-ref HEAD` == 'master' ]]
then
    echo 'You cannot commit to the master branch!'
    echo 'Stash your changes and apply them to another branch, using:'
    echo 'git stash'
    echo 'git checkout <branch>'
    echo 'git stash apply'
    exit 1
fi