How To Set A Default Command In Yii Command Runner

Ive got an cronjob running

it returns:

Yii command runner (based on Yii v1.1.12)

Usage: /var/www/path/to/site/cron.php <command-name> [parameters...]

The following commands are available:

- cron

- docs

To see individual command help, use the following:

  /var/www/path/to/site/cron.php help <command-name>

so it seems that it starts perfect, how can i make cron the default command if no command is given.

The Problem is i have no direct possibility to change the crontab.

Thanks in advance!