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Date: Mon, 23 May 2016 13:19:17 -0400
Message-ID: <CACoZoo3WTtzVZApmfAD+K8aRqau3x8BtcHKe47o5HO2m4N53Ew@mail.gmail.com>
Subject: =?UTF-8?Q?Re=3A_tar_incremental_backups_and_ctime=E2=80=8F_problem?=
From: Erik Soderquist <ErikSoderquist@gmail.com>
To: cygwin@cygwin.com
Content-Type: text/plain; charset=UTF-8

On Mon, May 23, 2016 at 4:40 AM, x y wrote:
> Hello,
>
> The MS Office applications are changing the ctime value of .doc and
> .xls files even if they are not modified. Opening and closing an
> office file without modifying the content is changing ctime and the
> unmodified document is included in the incremental tar archive.

I would say this is an MS Office flaw.  If _nothing_ is, neither ctime
nor mtime should be updated.


> Could it be possible to use the mtime value instead of ctime to avoid
> the the reappearance of the unchanged files in the incremental archive?

Use a find command to build a file list of all files changed since
last backup.  Personally I highly recommend differential against last
full rather than incremental, but that is a different discussion.

Also, you might reach out to Microsoft for why they are modifying any
timestamp if nothing was changed.

-- Erik

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