Shell Programming and Scripting

Hello,
I am trying to write a script to back up an OS X (10.1.5) Server using the ditto command. It's really just a simple script...

#! /bin/sh
ditto / network_volume


That seems to work as long as I'm logged in as root. I would like to have this run in cron periodically. Is there a way to make the script su without asking for a password? If I put su above the ditto command it will ask for the password and I have to manually type it in.

Thanks for any help you can provide.
Jason

Am I missing something here...

Why don't you run it in root's crontab, hence nullifying the need to su?

Can you use sudo?

If you're a member of the Admin group, use sudo.

Otherwise, put it in root's crontab.
Note that you may have to activate the root account if you have not done so already.

Also, maybe check into some other backup methods... I don't know if Ditto is smart enough not to try to recursively copy the network volumes on top of themselves - not to mention that it's a waste of bandwidth, as you're no doubt copying stuff that hasn't changed, like for example the /Developer documentation and examples (assuming it's installed - it was just an example anyways...).

Thanks guys. Very helpful information. I'll put your suggestions to use.