new_contents: #!/usr/bin/env python
  
  import sys
  import glob
  
  def die(msg):
      print msg
      sys.exit(1)
  
  def validations():
      validations = glob.glob('playbooks/*.yaml')
      return list(sorted(validations))
  
  
  def command_list(**args):
      for i, name in enumerate(validations()):
          print "%d. %s" % (i + 1, name)
  
  
  def command_run(*args):
      if len(args) != 1:
          die("You must pass one argument: the validation ID.")
      try:
          index = int(args[0]) - 1
      except ValueError:
          die("Validation ID must be a number.")
      if index < 0:
          die("Validation ID must be a positive number.")
      try:
          validation_path = validations()[index]
      except IndexError:
          die("Invalid validation ID.")
          sys.exit(1)
      print "Running validation '%s'" % validation_path
  
  def unknown_command(*args):
      die("Unknown command")
  
  
  if __name__ == '__main__':
      if len(sys.argv) <= 1:
          die("You must enter a command")
      command = sys.argv[1]
      command_fn = globals().get('command_%s' % command, unknown_command)
      command_fn(*sys.argv[2:])
  
subject: Add a basic runner program