[ubuntu-za] apt-get upgrade explanation

[Morgan Collett]

On Tue, Aug 18, 2009 at 15:28, Jonathan
Hitchcock<jonathan.hitchcock at gmail.com> wrote:
> Hi,
>
> On Tue, Aug 18, 2009 at 3:20 PM, Alf Stockton<alf at stockton.co.za> wrote:
>> Please tell me what it means when I see
>> The following packages have been kept back:
>>  linux-generic linux-headers-generic linux-image-generic
>> ubuntu-netbook-remix
>> when I do an upgrade.
>> Is it that these packages are not quite ready for release?
>
> When using aptitude (which is recommended over 'apt-get'), the
> "upgrade" command has now been deprecated, and replaced with the more
> descriptive "safe-upgrade" - this gives a hint as to why it is not
> installing those packages.
>
> From the man page of 'aptitude':
>
> "safe-upgrade:   Upgrades installed packages to their most recent
> version. Installed packages will not be removed unless they are
> unused. Packages which are not currently installed may be installed to
> resolve dependencies unless the --no-new-installs command-line option
> is supplied.
>
> It is sometimes necessary to remove one package in order to upgrade
> another; this command is not able to upgrade packages in such
> situations. Use the full-upgrade command to upgrade as many packages
> as possible."
>
> "full-upgrade:   Upgrades installed packages to their most recent
> version, removing or installing packages as necessary. This command is
> less conservative than safe-upgrade and thus more likely to perform
> unwanted actions. However, it is capable of upgrading packages that
> safe-upgrade cannot upgrade."
>
> So, the reason it is not upgrading those packages is because it will
> have to remove some other packages.
>
> If you want to see the exact reason, running:
>    aptitude why-not linux-generic
> should tell you why it won't install that package.
>
> (And this is why aptitude is recommended over apt-get too.)

Alternatively you can run "apt-get dist-upgrade" to do more or less
what aptitude full-upgrade does - install something which requires the
installation of something not already installed or removal of
something already installed.

I know aptitude is generally considered superior, but my fingers
haven't learnt to type it yet... and apt-get has Super Cow powers!
(try "apt-get moo"...)

Regards
Morgan