On Linux or Unix, a cron job helps you run a command or a shell script or a php script at regular intervals in an automated manner. Sometimes, setting this up gets tricky if you don't know how to do it correctly.
If you couldn't set up your cron job properly or if it doesn't work for some reason, just order this gig and i will set it up or fix it. However, for $5, I wouldn't do much research on whether the command you gave is correct or not as it would involve more effort. Eg: magento cron jobs.
Order will be cancelled if there is a genuine reason for cancellation.