Synaptic / Apt: Check for unused packages?

[Daniel Robitaille]

On 5/21/06, Chanchao <custom at freenet.de> wrote:
> I was doing a dist-upgrade of an older machine from Breezy to Dapper
> yesterday (won't be doing that again. :) and I noticed a lot of older
> packages/libraries were actually being re-installed.  The one that I
> noticed was GStreamer 0.8, where the current version is 0.10.   The only
> reason I noticed this is because I have the experience with the
> GStreamer version numbers because of messing around trying to get
> RestrictedFormats to work.  But who knows what else is on there double,
> what older packages might be still around..
>
> So, is there a way to use apt / Synaptic to check for packages /
> libraries that are no longer used by anything?  Does apt even
> distinguish between applications and libraries?  I think it should,
> because otherwise there would be no way to tell what is a top level
> application and what is a library.  For sure when nothing else depends
> on a library then it can be removed.
>
> This dist-upgrade took such a long time (both downloading and
> installing, then the install process sometimes required user-input so
> you have to mother over it all the time), plus I saw all kinds of error
> messages, plus then X/GDM tried to start but failed, HUGE amount of
> hassle.  It would have been quite a bit faster to just download a Dapper
> installer and then quickly apt-get the application I had before.  And
> then I wouldn't have that worrying feeling that there's all kinds of old
> crap still around.  I got rid of Gstreamer0.8 and a whole lot of old
> kernels manually, but what else is in there that I don't know about..
>
> Just the installation/configuration took 6 hours altogether, that was
> AFTER the downloading last night..

On a somewhat related topic, the prefered and clearner way to upgrade
from Breezy to Dapper is with the update-manager.  See for example:
  http://daniel.holba.ch/blog/?p=14




-- 
Daniel Robitaille