When Kubuntu needs to be upgraded between versions (e.g. 9.10 to 10.04), there's a notifier icon that shows up in the system tray,
(Source)
But if I click on it to start the upgrade and it fails for some reason (in my case, not enough space on the /boot partition), the icon disappears. How can I either get it back, or run the upgrade manually, without having to log out and log back in?
Yesterday I upgraded a laptop from Kubuntu 9.04 (Lucid) to 9.10 (Karmic). Then afterwards I tried to install some software
$ sudo aptitude install dont-remember-what-it-was
and I get
sudo: aptitude: command not found
Wait, what? How can aptitude be missing? And it's not just that - apt-get and dpkg also somehow mysteriously vanished from the system. I've manually checked in /usr/bin and all the other directories in $PATH and verified that the files actually do not exist.
$ ls /usr/bin/aptitude
ls: cannot access /usr/bin/aptitude: No such file or directory
Thankfully I have two graphical package managers available, Adept Installer and KPackageKit. Both of them report that the aptitude package is installed. I tried uninstalling and reinstalling it through the GUI, just to be safe, and the uninstall/reinstall seemed to go off without a hitch. But the actual program binaries are still missing.
Is this something normal? If not, has anyone ever heard of it happening? Is it likely that the missing programs will magically reappear if I upgrade to 10.04?
EDIT: I have no idea what was going on, but after leaving the computer off overnight and a couple of reboots, the problem seems to have fixed itself. All the right files seem to be there.
Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a package, that is.
Bonus question: what if it's a file that isn't installed on my system? Is there, say, a website that will let me look up a file and see what packages, if any, provide it?
What are the differences between apt-get, aptitude, and synaptic, and which one is the recommended choice for normal day-to-day package management?
This is a basic question, but I think it'd be good information to have on the site, and besides I am relatively new to Ubuntu so I could use an expert explanation.