SORRY.BAT illustrates a way to test for whether a door
is in use or not. This is sometimes needed on multi-node
systems when running a door that is not multi-node
compatible. Of course you will have to change the COM1
to reflect whatever comport is being used by the caller.
This will check for the existence of SORRY.TXT and if it's
found will tell the caller the door is in use and return
them to the BBS. If SORRY.TXT is not found, it will go
ahead and create it and then run the door, deleting the
SORRY.TXT after the caller exits the door.