You simply pre-pend the "time" command to your script. When your script ends, the execution time, cpu time, etc will be printed to STDOUT...

> time yourscriptname

your script's output....

real 0m0.005s
user 0m0.010s
sys 0m0.000s
>

The last 3 lines are the output of time command... Isn't that what you asked for?