Git hook to make a git repository master branch read only. This should go in .git/hooks/

pre-receive

#!/usr/bin/env ruby

old_sha1, new_sha1, ref = gets.split

if ref == "refs/heads/master":
  puts "Pushing to origin/master is not permitted."
  puts "This is a read-only branch."
  puts ""
  puts "Create a new branch instead, or commit to SVN."

  exit 1
end