[Discussion] Trouble using xcopy

[Stratton McAllister]

>>
I may not be understanding what you're trying to do, but you can use -u to
copy only files that are newer than the ones in the archive.  I use zip
-ruS to back up my system drives, similarly to what Julian does but
manually.
<<

Well, I'm not so sure.  The way I read the documentation, with this parameter 
the zip program doesn't use the archive bit, but checks each incoming file 
against the contents of the existing .zip file which it then updates if the 
incoming is new or changed.  The result is a .zip file with all the latest 
versions -- but any older versions are gone.  

Not what I want.  As long as I have the archive space, I want to retain each 
day's new and changed files so that I can go back and fix up something stupid 
I did a week ago.

>>
>From the Zip documentation::

       -t mmddyy
              Do not operate on files modified prior to the spec-
              ified date, where mm is the month (0-12), dd is the
              day  of  the  month (1-31), and yy are the last two
              digits of the year.  For example:

                           13 Apr 1996                          7

                     zip -rt 120791 infamy foo

              will add all the files in foo and  its  subdirecto-
              ries that were last modified on or after 7 December
              1991, to the zip archive infamy.zip.

You might have to do this manually unless you can write a script to get
the date from the system and insert that into the zip command, but it
would seem to archive only files modified after a specific date.
<<

That's a possibility.  I could even add a bit of code to my monthly complete 
backup to retain the backup date for use during differential backups.

Or, for that matter, I could just use, say, the first of the present month 
(mm01yy) in the daily backups and get what I actually need.  Hmm.  Not an 
actual differential backup but perhaps adequate for my purposes.

I'm a bit surprised zip doesn't seem to have any capability to use the 
archive attribute bit of a file.  It does use the system and hidden 
attributes.

Thanks 

Stratton