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Number   :  209
Date     :  2001-06-16
Author   :  Kan Yabumoto
Subject  :  Re: Help - BUG ?
Size(KB) :  3


No. It is not a bug. It's a feature (as all manufacturers say).

Some historic perspective might help explain why XXCOPY deletes the
empty directories when it simply "moves" files from one place to
another.

When we added the "remove" operations to the XXCOPY command set,
we made four variations. What we wanted to accomplish here was to
make XXCOPY's powerful file-selection features for filecopy also
applied to file deletion as well. That is, the all-or-nothing
proposition of the DELTREE can be substituted by XXCOPY.

The migration path can be depicted like this:

COMMAND.COM/COPY --> XCOPY.EXE --> XXCOPY.EXE
COMMAND.COM/DEL --> DELTREE.EXE --> XXCOPY.EXE


So, the four variations in the delete operations in XXCOPY are:

/RS Files in the src directory will be removed
/RC Source file removed after a successful copy
/RD Files to be overwritten in the dst will be removed
/RX Files absent in the source will be removed from dst

The /RS is the most standard case in the four and the remaining
three are variations of the first one. Or, putting another way,
at first, we conceived /RS and /RD as a pair where instead of
files being copied from the source to the destination, no
files will be copied but the files involved in the process
of file-selection will be removed.

So, these two are the easiest to understand especially under
the contest of the original file-copy mechanism. The /RX switch
was complimentary to the /RD switch which can be thought
of the /Z operation without copy. Then, being greedy in our
quest for more power, /RC was added as a bonus. It turned
out that it became quite popular once we say it's equivalent
to a MOVE.

One of the common features in these commands is to remove
empty subdirectories in the directory where files are removed
(otherwise, any directory with a subdirectory would not
be removed).

So, from this grouping, it makes sense to delete empty
subdirectories (whether or not it became empty as a result
of file deletion) in this context.

And it just happens that the net effect of the /RC operation
is nearly identical to a common file-MOVE operation. We are
still contemplating to officially introduce a dedicated
"MOVE" switch (if and when that became true, this discussion
will become totally moot, since the new move operation will
probably handle this case more intuitively).

I kinda agree that the deletion of empty directory is
counter-intuitive (and therefore, we should consider
generating a warning). But, a warning with yet another
user-prompt would provoke a "NOT-AGAIN" reaction. Also,
it would break the symmetry in the four /R switches
unless we put the prompt-before-deleting-an-empty-directory
on all of the four. That would certainly create a riot
around the Pixelab world headquarters!!! Therefore,
we will just leave it as it is and just shrug...

----------------------------------------------------------

OK, so much for history lesson. But, there is a simple
solution to this (to avoid the "side-effect" of disappearing
empty directories):

/ED

This switch preserves empty directories which is useful
in conjunction with any deletion operation
( /Z, /Z0, /CLONE, /RS, /RC, /RD, /RX ).

So, those who consider /RCY to be equivalent to "MOVE",
should revise the notion by taking a note that /RCY/ED is
more like it.


Kan Yabumoto

===========================================================
At 2001-06-15 08:36, Atma Singh wrote:
>I am trying to use xxcopy to MOVE selected data from
>the c drive to the d drive. The line I am using is
>
>XXCOPY C:\*.WK4 "D:\MY DOCUMENTS" /RCY /S
>
>The problem is that the program deletes empty
>dircetories on the C drive. WHY ? or what am I doing
>wrong ?
>
>Thanks in advance



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