4.2bsd Oddity (BUG?)

[Doug Gwyn <gwyn>]

> > The owner of the parent directory should be able to "mv"
> > the subdirectory elsewhere ...
> 
> I assume that Doug chose the words "should be able" very carefully.

Actually, not as carefully as I should have.  It would make
sense for kernels (such as 4.2BSD) that have direct support
for manipulating directories to provide a rename() system
call that allows this, or for set-UID mv/mvdir utilities to
allow this, but it doesn't surprise me that they don't.