Prevent deletion of file when it is being copied

[Dale Amon]

On Thu, Sep 27, 2012 at 09:51:58PM +0900, Emmet Hikory wrote:
>     Yes, this is contrived, etc.  On the other hand, I suspect many
> of us have managed to be both Alice and Bob in a scenario much like
> that above when interrupted in the middle by some significant
> distraction, or just a sufficient span of time.

Not contrived at all. Unix, unlike Windows, is multi-user and
concurrent. You must always, always assume that any two actions
you can imagine might overlap in time and deal with those
concurrency issues. It actually requires people who know what
P and V are. ;-)