I'm trying to write a shell script that acts as a watchdog timer. Basically it needs to look for a file being created by another process and if it finds it, it starts its timing cycle over. If it times out before seeing that file, it will run another script. I know I can assign a variable X=`date +%S` as a starting point and I know how to check for the file, but I just can't seem to put it all together so it works. Help?

This is pigeon code on how u might layout script. It wakes up every second incrementing the timer and checking it against the timeout value. If the file is present, then the timer is reset. If ur using the old bourne shell (/bin/sh) u'll have to use expr for the maths. TimeOut=30 Timer=0 while true do sleep 1 Timer=Timer+1 if FileExists then Timer=0 else if Timer = TimeOut then RunNewProg fi done