* apt-pkg/deb/debversion.cc:

[apt.git] / doc / apt_preferences.5.xml

diff --git a/doc/apt_preferences.5.xml b/doc/apt_preferences.5.xml
index 12ea606b7a05ea7294354eb8d41d3b4a6908b196..e773ad144c8357d723e662eccd24082f0ed5c396 100644 (file)
--- a/doc/apt_preferences.5.xml
+++ b/doc/apt_preferences.5.xml
@@ -14,7 +14,7 @@
    &apt-email;
    &apt-product;
    <!-- The last update date -->
-   <date>04 May 2009</date>
+   <date>16 February 2010</date>
  </refentryinfo>
 
  <refmeta>
@@ -32,7 +32,8 @@
 <refsect1>
 <title>Description</title>
 <para>The APT preferences file <filename>/etc/apt/preferences</filename>
-can be used to control which versions of packages will be selected
+and the fragment files in the <filename>/etc/apt/preferences.d/</filename>
+folder can be used to control which versions of packages will be selected
 for installation.</para>
 
 <para>Several versions of a package may be available for installation when
@@ -52,6 +53,24 @@ earliest in the &sources-list; file.
 The APT preferences file does not affect the choice of instance, only
 the choice of version.</para>
 
+<para>Preferences are a strong power in the hands of a system administrator
+but they can become also their biggest nightmare if used without care!
+APT will not questioning the preferences so wrong settings will therefore
+lead to uninstallable packages or wrong decisions while upgrading packages.
+Even more problems will arise if multiply distribution releases are mixed
+without a good understanding of the following paragraphs.
+Packages included in a specific release aren't tested in and
+therefore doesn't always work as expected in older or newer releases or
+together with other packages from different releases.
+You have been warned.</para>
+
+<para>Note that the files in the <filename>/etc/apt/preferences.d</filename>
+directory are parsed in alphanumeric ascending order and need to obey the
+following naming convention: The files have no or "<literal>pref</literal>"
+as filename extension and which only contain alphanumeric,  hyphen (-),
+underscore (_) and period (.) characters - otherwise they will be silently
+ignored.</para>
+
 <refsect2><title>APT's Default Priority Assignments</title>
 
 <para>If there is no preferences file or if there is no entry in the file
@@ -610,6 +629,13 @@ apt-get install <replaceable>package</replaceable>/sid
 </refsect2>
 </refsect1>
 
+<refsect1>
+<title>Files</title>
+  <variablelist>
+    &file-preferences;
+  </variablelist>
+</refsect1>
+
 <refsect1>
 <title>See Also</title>
 <para>&apt-get; &apt-cache; &apt-conf; &sources-list;