eval {

        local $SIG{'ALRM'} = sub { die "timed out\n" };

        alarm(10);
        system("sleep 30; echo 'I made it'") && die "system call failed\n";
        alarm(0);

};
if ($@) {
        if ($@ eq "timed out\n") {
                print "I timed out\n";  
        }
        else {
                print "something else went boom\n";
        }
}
else {
        print "I didn't time out\n";
}