Runs command.

        :param cmd: command to run (key at the registry)
        :param argv: arguments passed to the command

def run_command(self, cmd, argv):
        """
        Runs command.

        :param cmd: command to run (key at the registry)
        :param argv: arguments passed to the command
        """
        try:
            Command = self.get_command_class(cmd)
        except CommandError, e:
            self.stderr.write(str(e) + '\n')
            self.show_help()
            sys.exit(-1)
        command = Command(stdout=self.stdout, stderr=self.stderr)
        command.run_from_argv(argv)