I make no apologies for this...it came to me while I was...ermmm...meditating in the Monastery bathroom :)

open (HANDLE,$door);
flock (HANDLE,LOCK_EX);
push;
push;
push;
pop;
my $handle = new IO::File "lavatory", "w";
$handle->flush();
flock (HANDLE,LOCK_UN);
exit;
[download]

/me suddenly wonders if this crops up regularily, as it were....
update Darn - I forgot to close the door again...oh well, Larry'll close it for me:)