<page xmlns="http://projectmallard.org/1.0/"
      xmlns:its="http://www.w3.org/2005/11/its"
      type="topic" style="task"
      id="addremove-sources">

  <info>
    <credit type="author">
      <name>Ubuntu Documentation Team</name>
    </credit>
    <desc>
      Add repositories to extend the software sources Ubuntu uses for 
      installation and upgrades.
    </desc>
    <include href="legal.xml" xmlns="http://www.w3.org/2001/XInclude"/>
    <link type="guide" xref="addremove"/>
    <revision version="20.10" date="2020-09-13" status="review"/>
  </info>

  <title>
    Add software repositories
  </title>

  <p>
    Software is available from third-party sources, as well as from the default 
    Ubuntu software repositories. If you want to install software from a 
    third-party software repository, you must add it to Ubuntu's list of 
    available repositories.
  </p>

  <note style="warning">
    <p>
      Only add software repositories from sources that you trust!
    </p>
    <p>
      Third-party software repositories are not checked for security or 
      reliability by Ubuntu members, and may contain software which is harmful 
      to your computer.
    </p>
  </note>

<p>
</p>
   <p>
   To add a repository:
   </p>

  <steps>
    <item>
      <p>
        Open <app>Software &amp; Updates</app> via the <em>Activities</em> search bar.
      </p>
    </item>
    <item>
      <p>
        Switch to the <gui>Other Software</gui> tab.
      </p>
    </item>
    <item>
      <p>
        Click <gui>Add</gui> and enter the APT line for the repository. This 
        should be available from the website of the repository, and should look 
        similar to:
      </p>
      <p>
        <code its:translate="no">deb http://archive.ubuntu.com/ubuntu/ resolute main</code>
      </p>
    </item>
    <item>
      <p>
        Click <gui>Add Source</gui>. Enter your password in the Authenticate
        window.
      </p>
    </item>
    <item>
      <p>
        Close the <app>Software &amp; Updates</app> window. <app>App Center</app> will then
        check your software sources for new software.
      </p>
    </item>
    <item>
      <p>
        Most repositories provide a signing key to be able to verify downloaded packages.
        So in addition to the steps above, you should follow possible instructions on how to
        download and install the signing key (GPG key).
      </p>
    </item>
  </steps>

</page>
