How do I keep my system up to date with Raspbmc?

Question

Occasionally, my Raspbmc upgrades itself, downloading and installing new kernels and xbmc. How would I keep the other packages up-to-date?

I'm not sure if it's recommended, but I tried sudo apt-get upgrade followed by sudo apt-get dist-upgrade. It seems like some packages are put on hold, although surprisingly, others were still uninstalled. Should I not have run these commands?

$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages will be REMOVED:
  libnss-winbind libpam-winbind samba
The following packages have been kept back:
  libwbclient0 samba-common smbclient winbind xbmc
0 upgraded, 0 newly installed, 3 to remove and 5 not upgraded.
After this operation, 21.8 MB disk space will be freed.
Do you want to continue [Y/n]? 
(Reading database ... 33369 files and directories currently installed.)
Removing libnss-winbind:armhf ...
Removing libpam-winbind:armhf ...
Removing samba ...
[ ok ] Stopping Samba daemons: nmbd smbd.

Subsequent attempts at sudo apt-get upgrade and sudo apt-get dist-upgrade resulted in no packages being upgraded or installed.

$ dpkg --get-selections | grep hold
initscripts                 hold
insserv                     hold
libavahi-client3:armhf      hold
lsb-base                    hold
lsb-release                 hold
manpages                    hold
network-manager             hold
rsyslog                     hold
udev                        hold
upstart                     hold
winbind                     hold
xinetd                      hold

Answer 1

upgrade will never alter which packages are installed, it will only update those that are installed to the latest version it can. It will not upgrade a package if that would require installing new dependencies, and it will not remove unnecessary packages.

dist-upgrade will (un)install dependencies as needed. As far as I know, it’s equivalent to install [list of all explicitly installed pkgs] (but there may be differences). This is good, dependencies are bound to change, and you want your system to reflect that, obviously.

Aside: Some people say dist-upgrade is dangerous (e.g., if you have stuff that depends on certain packages, but does not declare this [which is bad form, I’d say]). If you’re in a production environment and want your system to be as stable as possible, then this might be a concern. For the record: If you are worried, use install [package you care about] to selectively "dist-upgrade" only some packages, rather than all.

Assuming you don’t use your Pi for mission-critical stuff, dist-upgrade does exactly what you want, so you’re good. There’s no need to run both, by the way, because d-u will do what u does and more.

As for packages being held back: This probably due to (at the moment) unresolvable dependencies, but should go away once those deps are available.