Check out the perl faqs which specifically address this situation.

perldoc -f system
[download]

It lists how to inspect the return value from a system call.

 if ($? == -1) {
     print "failed to execute: $!\n";
 }
 elsif ($? & 127) {
     printf "child died with signal %d, %s coredump\n"
         ($? & 127),  ($? & 128) ? 'with' : 'without';
 }
 else {
     printf "child exited with value %d\n", $? >> 8;
 }
[download]

Modify to suit.

Excellent answer. Just to be complete, this is the short version:

system("/my/shell/prog") && die "System failed: $!"
[download]