Keeping Your Computer Updated
No operating system or piece of software is perfect. Because of this, Ubuntu developers will release security and other updates as needed. These are placed into the Ubuntu repositories and are quite easy to install.
Most of the updates to your machine will be security related. This means that the developers have found a weakness in a particular program in Ubuntu and have released a fix for it. There will also be a small number of updates to fix some critical bugs. For a home user, there is generally no reason not to install these right away, as not installing them might leave your computer open to security breaches. While Ubuntu is significantly more secure from the main concerns of some operating systems, such as fears involving viruses and spyware, no computer is perfectly secure because no software is perfect. When problems are discovered that could lead to security issues, like buffer overflows or remote exploits, they are fixed and released as quickly as possible, even if the danger is quite remote. Ubuntu developers also have a very strict policy about not putting new release versions of programs with function changes or new features into stable versions of Ubuntu. This practice keeps your system more stable by not introducing new problems.
Helpfully, Ubuntu checks the Ubuntu repositories once a day to see if there are any new versions of software you have installed, and it tells you when you need to update your machine.
Ubuntu 10.04 handles package updates by launching update-manager. Users are notified of security updates on a daily basis and are also notified when new Ubuntu versions are released. Because 10.04 is an LTS release, by default it will only notify of new LTS releases, meaning that it would likely be silent until April 2012. This behavior may be changed using System > Administration > Update Manager and clicking Settings.
Learning about What Was Updated
The update window, shown in Figure 4-6, will also show you specifically what is going to be fixed. In the details pane, it will show you what got fixed and how. It might also list a CVE number. The CVE number is a unique identifier for a security vulnerability. You can look it up on http://cve.mitre.org to see what the exact flaw was. However, most people don't need to worry (and really don't care) about these details.
Figure 4-6 The update window
I Want to Install an Application That Is Not in the Repositories
Although the repositories contain a huge selection of packages, sometimes the package you need is not included. The first thing you should check is that you have enabled the additional repositories such as universe and multiverse. You can do this from your menu at System > Administration > Software Sources. In the Ubuntu Software tab, ensure that the boxes are checked for main, universe, restricted, and multiverse. (See help.ubuntu.com/community/Repositories/Ubuntu for more details.)
If you have enabled these extra repositories and your package is still not there, have a quick hunt around with a search engine to see if you can find a repository (known as a Debian or APT repository) for your package. If you find one, use the Repositories dialog box you have just played with to add the new repository, and then use Synaptic to install the package.
One common type of extra repository you may encounter is called a PPA, or personal package archive. There is good information available for using PPAs at https://help.launchpad.net/Packaging/PPA/InstallingSoftware.
If no repository is available, look for a Debian package (.deb) for the application, most likely available from the software company's Web site, such as Adobe does with its Reader software or Skype with its VOIP software. If you find one, download it, and double-click it to install. If no Debian package exists, look for an Autopackage. (An upcoming subsection, "I Downloaded an Autopackage, but I Don't Know How to Run It," provides details about Autopackage installation.)
Finally, if all else fails, you may need to download the source code and compile it using instructions found at https://help.ubuntu.com/community/CompilingSoftware.
Changing Your Menu Layout
Although the main Applications, Places, and System menus are logical by default, you may want to further customize them by moving entries into different submenus, not displaying certain items, and making other tweaks. All of this is easily done with the built-in menu editor.
To edit the menus, open the option at System > Preferences > Main Menu or right click on one of the menus and choose Edit Menus. Using either method, the menu editor will appear, as shown in Figure 4-7.
Figure 4-7 The menu editor lets you easily change the Ubuntu menus.
The menu editor is fairly intuitive. To adjust which items are shown, click on a submenu in the left-hand pane and change the Show checkbox for the items you want to show or hide. To add a new item, select the submenu the item should appear in, and then click the New Item button on the right-hand side. The box shown in Figure 4-8 will appear.
Figure 4-8 Feel free to add your own menu items.
Menu items can be applications (the default), applications running in terminals, or files. Select the appropriate setting for the Type box for your menu item, or leave it as Application. Provide a name for your menu item in the Name box, the command to run in the Command box (or the location of your file in the Location box if you changed the type to File), and a brief description in the Comment box. You can also use the Browse button to select the application to run (or the file to open). Finally, click the default icon off to the side, and select an icon for the item. Click OK to finish adding the new menu item.