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•Debian Package files: These files are associated with Ubuntu and have the .deb suffix.

•Tarballs: Zipped archive files that contain the source code of a programme. This source code needs to be compiled before use. Installing programmes by compiling them from source is not covered by this course.

Compiling and installing programmes from source tarballs can can be very complex to debug when things go wrong. Tarballs are simple structures which don’t specify what dependencies are required to enable compilation to take place. For this reason it can also be time consuming and complex to determine the necessary dependencies and either install or compile them also. Compiling from tarball is therefore not covered on this course.

It is not guaranteed that the single package files will be compatible with your system. Also, you will not receive security updates if you install these files. Therefore, wherever possible use a native Ubuntu package of the application available through a package manager.

6.8.1Installing/Uninstalling Debian Packages

Debian packages are installed and uninstalled using the graphical installer (gdebi). gdebi will attempt to install any dependencies which are in the Ubuntu repositories, however if the package requires further dependencies which are not in the Ubuntu repositories these will also need to be installed manually.

To install a Debian package, open the .deb file from the folder in which it resides.

1.Download the package XVidCap xvidcap_1.1.6_i386.deb. As this package is not in the Ubuntu repositories, you will need to download it from the following website: http://sourceforge.net/projects/xvidcap/.

2.Once downloaded, simply double click the .deb file and the gdebi installer will start. It will check to see if you have all the necessary dependents, and if so will offer an Install button. Simply press the button to start the installation. In the event that dependencies cannot be resolved, an error message will be displayed and you will not be able to install the package until they are fulfilled.

3.To uninstall the package, simply use the Synaptic Package Manager, as outlined previously in this section.

6.9Software Repositories

A software repository is a library of packages (applications) available over the Internet. The Ubuntu software repository contains tens of thousands of freely available packages for you to download and install. These packages have been specially built and selected for Ubuntu.

6.9.1Software Repository Categories

Ubuntu repositories are categorised into four groups based on the level of support that software development teams provide for a programme and the level of compliance the programme has with the free software philosophy.

•Main

•Restricted

•Universe

•Multiverse

The Main Component The Main component contains software packages that are free and fully supported by the Canonical team. These packages comply with the free software philosophy and are available by default while installing Ubuntu. For all packages in the Main component, security updates and technical support are available free of cost. OpenOffice.org, Abiword and the Apache web server are some of the packages available there.

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The Restricted Component The Restricted component consists of packages for commonly used software that are supported by the Ubuntu team but not available under a completely free license. Binary drivers produced by some video card vendors are an example of packages available there. Packages in this component are also available on the standard Ubuntu installation CD, but they can be easily removed.

The Universe Component The Universe component includes thousands of packages for software that is not officially supported by Canonical. The software is available under a variety of free licenses, taken from a variety of public sources. This component is available only through Internet downloading.

All the packages in this component are expected to work perfectly. However, there is no guarantee of security fixes and support for these packages. These packages are maintained by the community.

The Multiverse Component The Multiverse component contains packages of non-free software, which means that the licensing requirements of the software does not meet the license policy of Ubuntu’s Main component. It is the user’s responsibility to verify their rights to use the software and comply with the individual licensing terms. Support and security updates are not provided. Examples of these packages include VLC and the Adobe Flash plugin.

Many packages are not available in default Ubuntu repositories. These packages can either be installed from other Ubuntu repositories or from third-party software. To use the packages present in third-party software, you need to add the software and the repositories.

1. On the System menu, point to Administration and then click Software Sources.

Figure 6.49: Launching Software Sources Dialogue Box

The Software Sources dialogue box opens. The software sources for Ubuntu are selected by default.

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Figure 6.50: Selecting the Required Sources

NOTE:

You can also open the Software Sources dialogue box by using the Add/Remove applications or Synaptic Package Manager to enable the repositories under the Ubuntu Software tab.

2. To add a repository from the third party, click the Third-Party Software tab and then click Add.

Figure 6.51: Adding a Third Party Software Source

3.Type the APT line for the repository you want to add as a source. To access the Debian main repositories, type deb http://ftp.debian.org sarge main in the APT line box. Click Add Source. NOTE:

The APT line should include the type, location and components of a repository.

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Figure 6.52: Stating the Source APT Line

4. Click Close to save changes. The repository specified in the APT line is added to the third-party software box.

Figure 6.53: Software Sources Dialogue Box Displaying the Added Source

5.With the addition of an extra repository, you will be prompted to update information about available software. Click Reload to do so.