I was trying to upgrade just a single package, so I typed sudo apt-get upgrade packagename. (Now I know I'm supposed to use apt-get install for that.) Now apt-get is upgrading everything in my whole system. I stopped it with shutdown -h now (hey, it worked) as C-c doesn't seem to work very well.
However apt-get has a memory and now I can't do anything with apt-get such as install without it attempting to continue with a full system upgrade. How do I get apt-get to just abort the upgrade?
When I follow the instructions in the accepted answer as suggested by Itai Ganot, this is what happens:
$ sudo apt-get autoclean [sudo] password for dsw: E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem. dsw@dsw-VirtualBox:~$ cd /var/cache/apt/archives/partial dsw@dsw-VirtualBox:/var/cache/apt/archives/partial$ ls dsw@dsw-VirtualBox:/var/cache/apt/archives/partial$ ls -a . ..
Following the instructions in the message:
sudo dpkg --configure -a
eventually stops. So the above method does seem to stop the apt-get update eventually.