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Date: Wed, 16 Jul 2003 00:38:15 -0500
From: Dan Nelson <dnelson@allantgroup.com>
To: David Bear <David.Bear@asu.edu>
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Subject: Re: getting the mdate of a file
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In the last episode (Jul 15), David Bear said:
> I'd like to run tar using a data incremental. For example, if I run
> tar today like this:
> tar cvf /dev/nsa0 /home > home.catalog
>
> I end up with a listing of all files tarr'ed in home.catalog. Then
> the next day I'd like to run tar but only have tar select files that
> were changed since home.catalog was written. Tar has --newer DATE
> option but I would like to set the DATE according to the last
> modified time of the home.catalog.
>
> So, question 1 is how do I get the last mod date of a file?
>From the tar infopage:
`--newer=DATE'
`--after-date=DATE'
`-N'
When creating an archive, `tar' will only add files that have
changed since DATE. If DATE begins with `/' or `.', it is taken
to be the name of a file whose last-modified time specifies the
date.
> Question 2 is, is there a better way that I'm missing?
What I did when I used tar for backups was to use the
listed-incremental option, which tells tar to create a list of
filenames and timestamps, and on subsequent runs, only back up files
that differ from the listfile. Worked very well. To do a full backup,
just delete the listfile before running tar.
--
Dan Nelson
dnelson@allantgroup.com