Shell Programming and Scripting

I know how to setup file systems, samba, perform basic system administration but im very rusty on the scripting side of things.

could i ask what would be the diffrence if i installed it as a cron job?

Edit: doesnt matter, i understand if i set it to run as a cron job, it will just run the whole script through every time, but would the system shutdown on the first failed ping?

Yes, you don't have the outer while loop with the sleep.

Is this the correct way to setup the crontab, for the script to run every min?

Code:

1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60     *     *     *     *     /rhys/ping

or

Code:

1    *     *     *     *     /rhys/ping

I suggest you test crontab under a normal user account to get a feel for it.

Ok thanks, il do that now, in the script you provided do i replace cable-ip with the ip of my modem?

Yes, I do encourage you to understand the script line by line. Of course you may have the IP address in /etc/hosts to assist, rather than coding into the script. So if the address changes you only have to change it in one place.

To test the script i just put the ip address straight in.

I have defined the script in the cron file to run every min as root in vmware.

If i pull the wire on the modem and leave for 5 mins the machine will still be on fine.