To run backup you need to execute following command:
php -f xtbackup.php -- ini[]=/path_to/your_ini_file.ini
of course this should ideally be added to the cron with MAILTO directive setup so you get notification.
You can specify what level of verbosity should be used with following option output.cli.verbosity=WARNING
Possible values: CRITICAL, ERROR, WARNING, NOTICE, DEBUG default being NOTICE
See link to INI examples below