Translations by Scott Todd

In this section you can learn how to use a package manager to add or remove applications in Ubuntu with a few clicks. You can also learn about more advanced techniques of managing applications and discover some optional applications which you can add to Ubuntu.

<link linkend="gnome-app-install"><application>Add/Remove Applications</application></link> - The easiest way to install and uninstall programs.

Open <menuchoice><guimenu>System</guimenu><guimenuitem>Administration</guimenuitem><guimenuitem>Software Sources</guimenuitem></menuchoice> and press <guilabel>Third Party Software</guilabel>.

You will be notified that the information about available software is out-of-date. Press <guibutton>Reload</guibutton>.

Once you have downloaded the GPG key, import the key by selecting the <guilabel>Authentication</guilabel> tab, clicking on <guibutton>Import Key File</guibutton>, and then selecting the GPG key to be imported.

With the <guimenuitem>Add/Remove</guimenuitem> item in the <guimenu>Applications</guimenu> menu, you can install programs to do new things with Ubuntu. You can also remove programs you do not want. You need administrative access to use <application>Add/Remove Applications</application> (see <ulink type="help" url="ghelp:administrative">Administrative Tasks</ulink> for more details).

Programs that are already installed have a check mark next to their name. Uncheck a program if you want to remove it from your computer.

When you click <guibutton>Apply Changes</guibutton>, any new software will be downloaded from the Internet, and Ubuntu will make any other changes you selected. If you have not activated the online package archive, you may be asked to insert your Ubuntu CD-ROM to install some packages.

Some packages from the <emphasis>main</emphasis> and <emphasis>restricted</emphasis> Ubuntu package repositories can be installed from the Ubuntu installation CD. Simply insert your Ubuntu installation CD and open <menuchoice><guimenu>System</guimenu><guimenuitem>Administration</guimenuitem><guimenuitem>Synaptic Package Manager</guimenuitem></menuchoice>. To list only packages on the Ubuntu installation CD, click on the <guibutton>Origin</guibutton> button in the lower left corner of <application>Synaptic Package Manager</application>. The packages should be listed under the <guimenuitem>Ubuntu 8.04_Hardy_Heron</guimenuitem> section.

If the packages are not listed, it may be because the CD is not listed as a package repository (the CD should be listed as a repository by default). To add the CD as a package repository, follow the instructions in <xref linkend="repository-cds"/>, below.

To enable <application>Synaptic</application> and other package managers to install software from CDs which contain packages:

Press <menuchoice><guimenuitem>System</guimenuitem><guimenuitem>Administration</guimenuitem><guimenuitem>Software Sources</guimenuitem></menuchoice>.

Go to the <guilabel>Third Party Software</guilabel> tab and click on the <guibutton>Add CD-ROM</guibutton> button.

The packages should then be listed. To have <application>Synaptic</application> only list packages from the CD, click the <guibutton>Origin</guibutton> button on the lower left corner of <application>Synaptic Package Manager</application>, then find the name of the CD on the list in the upper left corner of <application>Synaptic</application>.

Further documentation on <application>APTonCD</application> can be found on its website, <ulink url="http://aptoncd.sourceforge.net">aptoncd.sourceforge.net</ulink>

To launch <application>Synaptic</application>, press <menuchoice><guimenu>System</guimenu><guimenuitem>Administration</guimenuitem><guimenuitem>Synaptic Package Manager</guimenuitem></menuchoice>. You need administrative access to use <application>Synaptic</application>; see <ulink type="help" url="ghelp:administrative">Administrative Tasks</ulink> for more details.

If you are comfortable using the Terminal, you can use <application>apt</application> (Advanced Packaging Tool) to install or remove software. You need administrative access to use <application>apt</application>; see <ulink type="help" url="ghelp:administrative">Administrative Tasks</ulink> for more details.

For more information, see the <ulink url="http://www.debian.org/doc/user-manuals#apt-howto">Debian <application>apt</application> manual</ulink> and the <ulink url="man:apt-get">apt-get manual</ulink>.

Installing/uninstalling <filename class="extension">.deb</filename> files

You can use your package manager to uninstall a <filename class="extension">.deb</filename> file once it has been installed. Alternatively, enter the following in a Terminal: <screen>sudo dpkg -r <replaceable>package_name</replaceable></screen>

Converting <filename class="extension">.rpm</filename> files to <filename class="extension">.deb</filename> files

Another type of package is the <emphasis>Red Hat Package Manager</emphasis> (RPM) file. These have the <filename class="extension">.rpm</filename> suffix. It is not recommended to install these on an Ubuntu system. In almost all cases, a native Ubuntu <filename class="extension">.deb</filename> package is available. However, if absolutely necessary, an <filename class="extension">.rpm</filename> file can be converted to a <filename class="extension">.deb</filename> package using the <application>alien</application> application. The resulting <filename class="extension">.deb</filename> file can be installed as described above.

To convert an RPM into a <filename class="extension">.deb</filename>:

Installing <emphasis>tarballs</emphasis>

Compiling programs requires some packages that are not installed by default. You can install most of these all at once by installing the <application>build-essential</application> package.

Double-click the <filename class="extension">.run</filename> file and press <guibutton>Run in Terminal</guibutton> to run the installer