A Few Fundamental MEL Commands Everyone Should Know

Here are a couple of useful MEL commands/operators that you'll end up using in a lot of the stuff you write.

continue ;
Skips one iteration of a loop.

break ;
Stops the loop and continues script where the loop ends.

Warning("You messed up, but it isn't too bad so I'll keep going.") ;
Warnings alert the user that something is awry, but it's not a deal breaker.

Error("You messed up bad, I need to quit now.") ;
The error command will stop a script in it's tracks, ending everything.

return ;
Ends a procedure/function/method, but not the entire script. Continues on where the procedure ends. Can also be used to return a value (return $myString).

CGSutra has a great article going into more depth on these and a lot more of the fundamental MEL concepts. Check it out here.