Cron - Any advanced options?

[Kurian Thayil]

Hi All,

I am using RHEL 5.2 Server and I have 3 cron jobs enabled and all are
relating to RSYNC. Now, all of these scripts are run once in every 7 minutes
all day. The problem occurs when the scripts doesn't finish to execute in 7
minutes. This will result in starting execution of the same script again and
this will malfunction the setup.

Is there an option in CRON, which always check if CRON has started the
process and is already running? Cron should execute the script only if the
the process isn't running already. Any hints on this?

Regards,

Kurian Thayil.