invoke instead of (system* ...

[Catonano]

recently I read that we should move to using this invoke procedure instead of the (system* some-script) in defining little scripts in packages and services definitions

But I can't remember where exactly

Where is this invoke procedure defined ?

I'm specifically interested in an exception to be raised in case my script goes awry

In fact I discovered just today that I was overlooking a problem in my service because one of my scripts was failing

Thanks