trigger a script based on the run status of another scipt

Im a newbee..
I have a script which runs few times daily. I want to write another script which should pick up the latest log generated from the last run of the first job and trigger a thrid script if the first script runs successfuly.

Please help...

Cheers

grep success logfile >/dev/null && third

Without more information about the log file, we can't really offer much more.