[maemo-developers] [maemo-developers] Re: [maemo-announce] New Nokia 770 software image available

[From: Frantisek Dufka]

Antonio Orlando wrote:
>> I think that using tar to back up and restore applications installed
>> with apt/dpkg would be a Bad Idea.
> 
> Can I ask why? I have not enough Linux knowledge to answer this 
> (stupid?) question myself.

dpkg packages has postinst and prerm scripts that get executed while 
installing/removing package. It it hard to guess what they do (and 
modify) so you may not know what exactly to backup and may loose some 
effects of those scripts when restoring just the files from packages. 
But generally it may work in 99% of cases so it is not completely wrong. 
But there is a better solution, see below.

>  I've also tarred all 
> my linux installation (excluding some stuff) hoping it could be used as 
> a backup [1], has it been a Bad Idea?

That's not same as above. tarring whole disk will work. Backing up only 
rendom selected part not.

> 
>> It should be pretty easy to get a list of installed packages from apt
>> (or the application installer) before the flash, and then reinstall them
>> in one swoop with apt-get install.  I plan to figure this out over the
>> weekend.
> 
> Le me know on the list if you succeed, please.
> 

Best would be to use dpkg-repack [1] script which rebuilds packages from 
installed system (including modified config files) so you can reinstall 
them later. I'm not sure whether in can be made to run on N770, it may 
have nasty dependencies on advanced debian stuff.

Frantisek

[1] http://packages.debian.org/stable/admin/dpkg-repack