DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
</programlisting></informalexample>
- <para>In general the sample configuration file in
- <filename>&docdir;examples/apt.conf</filename> &configureindex;
+ <para>In general the sample configuration file &configureindex;
is a good guide for how it should look.</para>
<para>Case is not significant in names of configuration items, so in the
<para><literal>Acquire::http::AllowRedirect</literal> controls whether APT will follow
redirects, which is enabled by default.</para>
- <para>The used bandwidth can be limited with <literal>Acquire::http::Dl-Limit</literal>
- which accepts integer values in kilobytes. The default value is 0 which deactivates
- the limit and tries to use all available bandwidth (note that this option implicitly
- disables downloading from multiple servers at the same time.)</para>
+ <para>The used bandwidth can be limited with
+ <literal>Acquire::http::Dl-Limit</literal> which accepts integer
+ values in kilobytes per second. The default value is 0 which
+ deactivates the limit and tries to use all available bandwidth.
+ Note that this option implicitly disables downloading from
+ multiple servers at the same time.</para>
<para><literal>Acquire::http::User-Agent</literal> can be used to set a different
User-Agent for the http download method as some proxies allow access for clients
<literal>options</literal> this must be specified in list notation. The commands
are invoked in order using <filename>/bin/sh</filename>; should any fail APT
will abort. APT will pass the filenames of all .deb files it is going to
- install to the commands, one per line on standard input.</para>
+ install to the commands, one per line on the requested file descriptor, defaulting
+ to standard input.</para>
- <para>Version 2 of this protocol dumps more information, including the
+ <para>Version 2 of this protocol dumps more information, including the
protocol version, the APT configuration space and the packages, files
- and versions being changed. Version 2 is enabled by setting
- <literal>DPkg::Tools::options::cmd::Version</literal> to 2. <literal>cmd</literal> is a
- command given to <literal>Pre-Install-Pkgs</literal>.</para></listitem>
+ and versions being changed. Version 3 adds the architecture and <literal>MultiArch</literal>
+ flag to each version being dumped.</para>
+
+ <para>The version of the protocol to be used for the command
+ <literal><replaceable>cmd</replaceable></literal> can be chosen by setting
+ <literal>DPkg::Tools::options::<replaceable>cmd</replaceable>::Version</literal>
+ accordingly, the default being version 1. If APT isn't supporting the requested
+ version it will send the information in the highest version it has support for instead.
+ </para>
+
+ <para>The file descriptor to be used to send the information can be requested with
+ <literal>DPkg::Tools::options::<replaceable>cmd</replaceable>::InfoFD</literal>
+ which defaults to <literal>0</literal> for standard input and is available since
+ version 0.9.11. Support for the option can be detected by looking for the environment
+ variable <envar>APT_HOOK_INFO_FD</envar> which contains the number of the used
+ file descriptor as a confirmation.</para>
+ </listitem>
</varlistentry>
<varlistentry><term><option>Run-Directory</option></term>