Variables in an external monitor BASH script

After reading LTM External Monitors: The Basics

I think I will just change the logic to rely on $?. Example below:

if [ $PAGE = "bxb" ]
then
         Echo up to STDOUT for the pool member to be listed as up.
        echo "Up"
         Check that the VCS Members are listed as origins in the snat_ids_primary definition.
        $TMSH list ltm snat snat_ids_lfep_out | $GREP -E "$VCS1|$VCS2|$PRI_IP" 2>&1 > /dev/null
        if [ $? -eq 0 ]
        then
                rm -f $PIDFILE
                exit 0  
         Check that the VCS Members are listed as origins in the snat_ids_alt definition. If so the SNAT config needs to be changed.
        else
        ......rest of the script