basic return value help

jonnybignote · 09-16-2010, 02:59 PM

Hi all
At the end of my daily cron jobs, (4am) I'm performing a reboot.

currently it does this regardless of machine status

I'd like to run it with a loop that will query 'mythshutdown --check' and proceed to reboot only if there is no recording or other activity in Mythtv. Return value 0 means ok to shutdown and value 1 means not.

Apologies for my very basic scripting knowledge as I'm sure this is very rudimentary, but here is what I have...

Code:

#!/bin/sh
while    
mythshutdown --check
do
sleep 10
done
sudo reboot

Currently the script is working in reverse so I think I either need to specify the return value or approach in another way.

Any help greatly appreciated

Thanks

druuna · 09-16-2010, 03:13 PM

Hi,

There are other ways to solve your problem, here's one that is based on what you have:

Code:

#!/bin/sh
while ! ./mythshutdown --check
do
sleep 10
done
sudo reboot

Hope this helps.

jonnybignote · 09-16-2010, 04:49 PM

perfect! - thanks

so does the '!' reverse the return value of the mythshutdown -- ?

either way that's exactly what I wanted

thanks again!

druuna · 09-17-2010, 12:58 AM

Hi,

The ! stands for not. It reverses the way the while statement works it doesn't touch the values generated by your script.

BTW: You're welcome