I installed ubuntu 12.04 using crouton on my chromebook. I'd like to update the distribution, because I can't always install the packages I'd like too. I followed various instructions online, and in chat, but I kept running into dead ends - for instance, I can't seem to find an update manager anywhere on the linux side of my system (I'm using xfce as my desktop, if that's relevant) which seems to be required for a lot of methods I found. I also tried the command sudo apt-get update && sudo apt-get full-upgrade, which went for about 30 seconds and outputted:
Reading package lists...Done
Building dependency tree
Reading state information...Done
0 upgraded, 0 newly installed, 0 to remove, and 0 not upgraded.
E: Invalid operation full.
Before I decided that I wanted to update my distribution for sure, I tried to install the package nethack, and it gave the error E: package 'nethack' has no installation candidate.
If there's any more information anyone needs, I'd be glad to figure it out and get it for them; I didn't know what all information was needed. I am fairly new to Linux.
Any help would be appreciated. Thanks!
EDIT:
I read through (and tried) the various commands given at the page that this is supposed to be a duplicate of. The only one that seemed like it might help, the last one, gave an error of "command not found". This question is not solved by that answer.
Extra piece of information: as noted in the comments, I believe I have an ARM CPU.
