upgrade vs dist-upgrade

[Mario Vukelic]

On Mon, 2006-04-10 at 17:55 +0100, Daniel Carrera wrote:
> I was hoping someone could tell me more about the difference between
> an 
> upgrade and a dist-upgrade.


Daniel,

hi again. The man page for aptitude states it quite clearly, I don't
think there is a need for me to rephrase it, but there's an example
below :)

--

upgrade
Upgrades installed packages to their most recent version. Installed
packages will not be removed unless they are unused (see the section
‘‘Managing Automatically Installed Packages’’ in the aptitude reference
manual); packages which are not currently installed will not be
installed.
If a package cannot be upgraded without violating these constraints, it
will be kept at its current version. Use the dist-upgrade command to
upgrade these packages as well.

dist-upgrade
Upgrades  installed  packages to their most recent version, removing or
installing packages as necessary. This command is less conservative than
upgrade and thus more likely to perform unwanted actions. Users are
advised to either use upgrade instead or to carefully inspect the list
of packages to be installed and removed.

--

Real example:

The metapackage ubuntu-desktop depends on everything vital for a Ubuntu
system. Therefore, by installing ubuntu-desktop it can be ensured that
the system is complete.

In Breezy ubuntu-desktop depends on several configuration applications,
like gnome-netstatus-applet, gnome-nettool, gnome-panel,
gnome-pilot-conduits, etc.
In Dapper it depends on additional stuff not included in Breezy, like
gnome-power-manager, and gnome-screensaver.

If you tried to do a simple upgrade from Breezy to Dapper, apt
would /not/ be able to update ubuntu-desktop, because this would involve
installing gnome-power-manager and gnome-screensaver.
A dist-upgrade however would do what is necessary to install
ubuntu-desktop, save from removing required packages.

Of course it -would- happily remove a lot else if the dependency tree
during the dist-upgrade had a grave error. Therefore the aptitude man
page writers recommend to the check the "to be removed" list