Re: corrupt/lost dpkg files, dpkg broken, aptitude broken, help :(

[Brian <ad44@cityscape.co.uk>]

On Sat 08 Jun 2013 at 18:39:45 -0500, Stan Hoeppner wrote:

> On 6/8/2013 4:43 AM, Brian wrote:
> > 
> > apt/aptitude have their own idea of what packages are available and do
> > not use what is in /var/lib/dpkg/available. So you should not have any
> > problem with installing.
> 
> Others mentioned this.  If this is the case, why does "aptitude remove
> --purge" throw an error trying to read /var/lib/dpkg/available.  This
> would suggest aptitude calls dpkg during package removal.  Is this the case?

When apt and aptitude install they use

   dpkg -i package.deb

and dpkg wants to open /var/lib/dpkg/available as it may need to write
to it to update the list of packages it knows about. The file can be
empty (making it useless to dselect and 'dpkg --print-avail') but is has
to exist for a package to install.

Removing a package involves

   dpkg -r package_name

My understanding is that dpkg does not need to open the available file
in this case, so I cannot understand why your aptitude command does not
complete successfully.

> > You could forget about /var/lib/dpkg/available and carry on as you
> > usually do. Alternatively, if it bothers you, either install dselect
> > and do
> > 
> >    dselect update
> > 
> > or download a Packages.gz file and execute
> > 
> >    dpkg --update-avail Packages
> 
> I strictly use "aptitude" for package management.  But it appears
> aptitude is not entirely standalone.  Or, is aptitude simply attempting
> to keep all of the package lists up to date across the other package
> management tools?

/var/lib/dpkg/available is mainly of use to dselect. apt and aptitude
maintain  their own separate, independent package lists in /var/lib. It
was incorrect of me to say 'apt-get update' or 'aptitude update' would
rebuild /var/lib/dpkg/available.