## my $w = $notify->watch ($file_to_watch, IN_MODIFY, \&on_change) or die $!;
 my    $w = $notify->watch ($file_to_watch, IN_MODIFY | IN_MOVE_SELF, \&on_change2) or die $!;

...
sub on_change2 {
  my($e) = @_;

  print $e->fullname, " changed ";
  print " and also moved!" if $e->IN_MOVE_SELF;
  print "\n";
}