Some odd things on 5.0 that work, but I'm not sure how safe they are... :-)
 
Ever wanted to replace a program file that someone's using?  Piece of
cake.  Get in the shell, rm the currently-accessed one, and mv the new
one in it's place.  It works, and subsequent accessors get the new file.
 
This also works for XL files in use by a program (verified that one too).
 
This is getting WAYYY too much fun.
 
[\] Jeff Kell
 
PS - I don't think I'd try this with (XL/SL).PUB.SYS though...