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Re: sync apt/dpkg state between systems?

Thilo Six wrote:
> Excerpt from Bob Proulx:
> >   # rsync -av /mnt/backup/etc/ /etc/
> >   # rsync -n --delete -av /mnt/backup/etc/ /etc/
> >   # rsync --delete -av /mnt/backup/etc/ /etc/
> I believe this not to be a good idea. When you do this you mess around with
> config files under the control of dpkg. With all the mess that creates.

Thank you for the review comment!  However I respectfully disagree.
And apparently you do as well because you immediately suggested
etckeeper which does exactly the same thing of managing files in /etc.
It is the same thing but simply using a different tool.

Most files in /etc are "conffiles".  They are within the realm of
control of the user.  Changes to them are understood and respected by
the package manager.  There isn't any "mess" caused by interaction
with dpkg.

However that isn't true of all files.  And in particular there are
uuids associated with lvm and md.  The /etc/lvm and /etc/mdadm
directories and any other UUIDs in /etc/fstab contain UUIDs and other
information specific to the new machine and new filesystems.  Those
would need to be avoided when restoring from backup.  Otherwise the
new system would have the UUIDs from the old system and that wouldn't

  * Exclude /etc/fstab
  * Exclude /etc/lvm
  * Exclude /etc/mdadm

> I would reinstall everything you had/need again and then diff prior to mass
> overwriting the files.

It is certainly a safe procedure to diff and review and merge from the
old to the new.  And making that the smallest possible set of merges
by installing the smallest possible system first is easiest.

Alternatively if working on the configuration files in /etc causes
stress then it is certainly reasonable to avoid any merging at all and
simply re-install what you had before and and re-configure whatever
you want again.  It won't be an exact copy then but everything will be
freshly installed and fresh in your mind.


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