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Re: dist-upgrade and sources.list



On Wed, Jun 08, 2005 at 06:20:47AM -0700, Basajaun wrote:
> Maurits van Rees wrote:
> > And on dist-upgrade: this is not meant just to upgrade to a new
> > distribution. I used to think that too. It is a more thorough (and
> > possibly more dangerous) method of upgrading. Say you have package-a
> > version 1 installed, with no dependencies. A new version 2 becomes
> > available, which has a new dependency on package-b, which you don't
> > yet have installed. An 'apt upgrade' will do nothing. An 'apt
> > dist-upgrade' will upgrade package-a from version 1 to version 2 and
> > will install package-b.
> 
> So, my guess is that "apt-get dist-upgrade" is a kind of "do whatever
> you have to do to make what I have in 'Default-Release' (or wherever)
> be my current release". So dist-upgrade, by itself, is useless, unless
> you have changed something in your preferences, right?

Partly true.

When you upgrade from the previous stable (woody) to the current
stable (sarge) you need to do a dist-upgrade. When everything works
out fine and there are no packages reported as held back, the
transition is complete. Then it doesn't matter anymore if you use
'apt-get upgrade' or 'apt-get dist-upgrade'.

But let's say you want to start tracking the new testing distro (or
unstable or experimental). If you only use apt-get upgrade then after
a while you will start noticing that some packages are being held
back. In other words: some newer version is available, but it isn't
getting installed. The reason is the one I gave above: a new
dependency was introduced in that package, so it now needs another
package that is not yet installed. 'apt-get upgrade' will refuse to
install that dependency, so it won't upgrade your installed package
either. The result: you are no longer tracking the testing distro and
you start lagging behind. This is not inherently bad or anything, but
you may want to avoid it.

You can handle that in two ways. Manually: 'apt-get install <that new
dependency package>'. Automatically: 'apt-get dist-upgrade'. This is
only necessary with testing/unstable/experimental. In the stable
distro the dependencies are garanteed not to change.

A strategy might be: use 'apt-get upgrade' when you are in a hurry or
want to stay on the safe side. Use 'apt-get dist-upgrade' from time to
time when you want to catch up with the rest of the Debian pack
again. :)

-- 
Maurits van Rees | http://maurits.vanrees.org/ [Dutch/Nederlands] 
Public GnuPG key: keyserver.net ID 0x1735C5C2
"Let your advance worrying become advance thinking and planning."
 - Winston Churchill

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