I know that
zypper up updates the current installed packages and
zypper dup is supposed to upgrade the whole system to a new version.
But from a technical point of view, what are the differences between these two commands? What happens on my system when I run one or the other?
I'm currently using opensuse 13.2 and I'm considering a switch to tumbleweed; I've read different opinions on what is the best way to update the system, up or dup, and I'd like to learn more about it to have a better understanding of the subject.