Don't commit to master! (located in .git/hooks/, need +x)

pre-commit

#!/bin/bash

protected_branch='master'  
current_branch=$(git symbolic-ref HEAD | sed -e 's,.*/\(.*\),\1,')

if [ $protected_branch = $current_branch ]  
then  
    read -p "You're about to commit in master, is that what you intended? [y/N] " -n 1 -r < /dev/tty
    echo
    if echo $REPLY | grep -E '^[Yy]$' > /dev/null
    then
        exit 0 # commit will execute
    fi
    exit 1 # commit will not execute
else  
    exit 0 # commit will execute
fi