gistfile1.txt

#!/usr/bin/env ruby
#
# An example hook script to check the commit log message.
# Called by "git commit" with one argument, the name of the file
# that has the commit message.  The hook should exit with non-zero
# status after issuing an appropriate message if it wants to stop the
# commit.  The hook is allowed to edit the commit message file.
#

commit_msg = File.read(ARGV[0])

unless /\A\[#\d+\].*/m.match(commit_msg)
  puts 'Commit message rejected by commit-msg git hook because it does not start with a story id. Valid example: "[#123456789] make it so"'
  exit -1
end

put this in .git/hooks/ in a file called commit-msg, which will need execute permissions.