function sysub {
   my $cmd = shift;
   my $rc = 0xffff & system $cmd;
   if ($rc == 0xffff) {
      print "command failed: $!\n";
   } elsif ($rc > 0x80) {
        $rc >>= 8;
        print "ran with nonzero exit status $rc\n";
   } elsif ($rc != 0) {
        print "ran with ";
        if ($rc & 0x80) {
           $rc &= ~0x80;
           print "coredump from ";
        }
        print "signal $rc\n";
   }
   return ($rc != 0);
}