upgrade vs dist-upgrade

[Eric Feliksik]

Daniel Carrera wrote:
> Hello,
> 
> I was hoping someone could tell me more about the difference between 
> an upgrade and a dist-upgrade.
> 
> I know that upgrade is safer, I know that dist-upgrade is intended 
> for upgrading the distro (e.g. Breezy to Dapper). I know that 
> dist-upgrade does a more agressive dependency resolution and that 
> might break things, but this agressiveness is necessary when you 
> upgrade to a new distro (e.g. Dapper).
> 
> But could someone give me a concrete example (made up examples are 
> fine) of something that dist-upgrade would do but upgrade would not? 
> I want to know more about what's happening under the hood.
> 
> Thank you for the help.
> 
> Cheers, Daniel.

from `man apt-get':

"dist-upgrade  in addition to performing the function of upgrade,
also intelligently handles changing dependencies with  new  ver‐
sions  of  packages;  apt-get  has a "smart" conflict resolution
system, and it will attempt to upgrade the most important  pack‐
ages  at  the  expense  of less important ones if necessary. The
/etc/apt/sources.list file contains a  list  of  locations  from
which  to  retrieve  desired package files. See also apt_prefer‐
ences(5) for a mechanism for overriding the general settings for
individual packages."

To satisfy dependencies dist-upgrade can remove packages. That's the
reason it can break stuff.