module Thor::Base::ClassMethods

def start(given_args=ARGV, config={})
  self.debugging = given_args.include?("--debug")
  config[:shell] ||= Thor::Base.shell.new
  yield(given_args.dup)
rescue Thor::Error => e
  debugging ? (raise e) : config[:shell].error(e.message)
  exit(1) if exit_on_failure?
end