It checks 

Cpu utilization (warns at 90 percent)
To make sure the bridge is up and running
Brain table capacity
Arbitrator is running
Process for do mac shaping is running
Disk space
Penalty buffer capacity. 


If any of these checks fails it prints a warning a
message and will return 1

If all the checks report ok it will return 0.

To put it in a loop to constantly modify you could do
the following in a shell script and take action only
when there is a problem

while true
do
./sanity > /dev/null
if [ "$?" = "1" ]
 then
 # call sendmail or something here
 fi
sleep 100
done