How do I update Ubuntu Server?

Question

I've Ubuntu Server 11.04. I want to update packages but not the core.

For example, I installed subsonic with apt-get. And I see there is a new version. I could install it manually by downloading the archive and using dpkg. But hey, its better to learn how to use new tricks.

P.S. apt-get upgrade will not list subsonic. Why?

Solution

Most of your installed software (not including Subsonic) is provided by configured software sources (also called repositories) from which software is automatically downloaded and installed by the package manager. Running these commands will upgrade all such software to the latest versions provided in your configured software sources:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

See the apt-get manpage for explanation of specifically what those commands do. (Also accessible on your machine via man apt-get.)

However, Subsonic was not installed in this way. Following these instructions, you manually downloaded the installer package (.deb file) for Subsonic, and installed it by manually invoking the dpkg command with the -i flag. Unlike most software for Ubuntu, Subsonic doesn't have a software source you can set up to provide it, so that's the way you have to install it. To upgrade it to a later version, simply download the newest .deb file (or whatever version you want to upgrade to) and follow those same installation instructions (with the new .deb file).

Since Subsonic is not automatically upgraded with the rest of the software on your system (via apt-get), you'll have to take care to remain current on issues that affect it so that you know when security vulnerabilities are discovered and when they are patched (i.e., when a new version is released to fix the vulnerability). In practice, all network server software of greater than an extremely minimal degree of complexity has multiple security vulnerabilities, which are discovered (and hopefully also fixed) from time to time.

Sometime in the future, you may have the preferable alternative of using a non-official software source (of a kind called a PPA) for Subsonic. You would then receive updates to Subsonic along with updates to the rest of the software on your system (via apt-get). However, currently the Subsonic PPA is empty and does not provide any software.

Comments

[Eliah Kagan]

Subsonic not in official repositories, so what version do you have, how did you install it (please provide links to any guides you used), and where do you see that there is a new version? I'm guessing you're referring to the media server, but you might alternatively mean the object-relational mapper (which could probably run under Mono or Portable.NET just as the other Subsonic runs under Java).

[Admin]

Yes I mean media server. I used subsonic.org/pages/installation.jsp#debian tutorial. So basically to update it, I need to re download the package and run dpkg? with some parameter maybe so it upgrades it?