From the aptitude man page:
Code:
update
Updates the list of available packages from the apt sources (this is
equivalent to "apt-get update")
upgrade
Upgrades installed packages to their most recent version. Installed
packages will not be removed unless they are unused (see the section
"Managing Automatically Installed Packages" in the aptitude
reference manual); packages which are not currently installed will
not be installed.
If a package cannot be upgraded without violating these constraints,
it will be kept at its current version. Use the dist-upgrade command
to upgrade these packages as well.
The problem ended up being a corrupted filesystem, probably caused by a bad memory module. I wouldn't have been able to fix the problem without "going to the command line".