<literal>sourcelist</literal> gives the location of the sourcelist and
<literal>main</literal> is the default configuration file (setting has no effect,
unless it is done from the config file specified by
- <envar>APT_CONFIG</envar>.</para>
+ <envar>APT_CONFIG</envar>).</para>
<para>The <literal>Dir::Parts</literal> setting reads in all the config fragments in
lexical order from the directory specified. After this is done then the
<literal>dpkg</literal>, <literal>apt-get</literal> <literal>dpkg-source</literal>
<literal>dpkg-buildpackage</literal> and <literal>apt-cache</literal> specify the location
of the respective programs.</para>
+
+ <para>
+ The configuration item <literal>RootDir</literal> has a special
+ meaning. If set, all paths in <literal>Dir::</literal> will be
+ relative to <literal>RootDir</literal>, <emphasis>even paths that
+ are specified absolutely</emphasis>. So, for instance, if
+ <literal>RootDir</literal> is set to
+ <filename>/tmp/staging</filename> and
+ <literal>Dir::State::status</literal> is set to
+ <filename>/var/lib/dpkg/status</filename>, then the status file
+ will be looked up in
+ <filename>/tmp/staging/var/lib/dpkg/status</filename>.
+ </para>
</refsect1>
<refsect1><title>APT in DSelect</title>