A howto backup your software configuration. "installed-software".

[Bas Roufs - En.]

Hello Everybody,

thanks for all the feedback so far. Taking into account ideas and developments 
of the last 24 hours, I added various details to the article at Ubuntu Forums 
- see http://tinyurl.com/8yjrfpf

One of the items I added has to do with the 2nd, 3rd., etc. system language - 
they did not come back in the spell checkers of packages like Kmail, Firefox 
and Libre Office after instaldebconf-get-selections > selection.debconf
debconf-set-selections < selection.debconfling according to the list of 
installed packages. How I solved the problem: see http://tinyurl.com/8yjrfpf, 
under the heading "More then 1 system language?"

Now I go through the feedback that has come in so far.

> will there be an issue if I use this techinique to move from 10.10 to 12.04
> ubuntu? I mean 12.04 will have newer versions of softwares by default like
> PHP, mysql, perl etc. will this method try to install old software - IN
> ADDITION - to new software which comes preloaded into new OS? how will such
> situation be handeled?

If a package has exactly the same name, eg. "MySQL", you will get the newest 
version of it after the upgrade. However, a countless number of packages will 
have different names, some others will be obsolete, etc. That's why it is not 
at all a good idea to use a list of installed packages from 10.04 for 12.04. I 
urge you to act as I  propose in the article at Ubuntu Forums:
+ first update your 10.10 system;
+ in the mean time, backup all your data at 1 or 2 external HD's
+ than, upgrade to 12.04 - follow the howto at Ubuntu.com or Kubuntu.org
+  AFTER UPGRADING, generate the list of installed-software;
+ take care of having a backup of all your recent data;
+ make a fresh install and use the list of installed packages.

> debconf-get-selections > selection.debconf
> debconf-set-selections < selection.debconf

It's always good to know more than one alternative for the same purpose. I 
will try it out -with and without SUDO- and get back to it. 

> > will there be an issue if I use this techinique to move from 10.10 to
> > 12.04 ubuntu? I mean 12.04 will have newer versions of softwares by
> > default like PHP, mysql, perl etc. will this method try to install old
> > software - IN ADDITION - to new software which comes preloaded into new
> > OS? how will such situation be handeled?
> 
> First you restore all your packages in the same version (for example
> 10.04LTS).
This is a good idea.

> Secondly you upgrade (for example 10.04LTS -> 12.04LTS).
I agree with this. However, I would also advise 2 other steps:
+ generate a new list of installed packages after the upgrade a.s.a.p.
+ carry out a fresh install of 12.04 after updating the list of installed 
packages and backup.

Why the 2nd step: a system configuration after an upgrade is not very stable. 

> 
> HOWEVER... will there be an issue? No.
> Not. At. All. (in my not so humble experience)
> The file with the dpkg-selections output does not contain any version
> numbers, so if you install, it will take the current version.
> 
> HOWEVER... you should not blindly install everything. 
> The dpkg-selections output is a text file. You are supposed to read it,
> understand it and edit it, removing everything you don't need. For
> example, delete all libs. Delete apache2, php, mysql,... if you have
> another package like phpmyadmin that depends on it. And so on.
> 
> HOWEVER... if you break your system, you get to keep all pieces.

In theory, you may be right. In practice, my experience with a revised version 
of such a list is not very good. The best things to do:
+ only use a list generated at the same distro and version;
+ generate an updated version of this list whenever you install or remove some 
package.

Respectfully yours,
Bas.



-- 
============================
Bas G. Roufs MA
Van 't Hoffstraat 1
NL-3514 VT Utrecht
The Netherlands
E. BasRoufs at gmail.com
Mob. +31 6 446 835 10 
Tel. +31 30 785 40
Open source OS: Kubuntu 12.04

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