Document that chpasswd does not use PAM to update the passwords. This fixes

http://bugs.debian.org/396726.  Debian patch 411_chpasswd_document_no_pam.

man/chpasswd.8.xml

@@ -79,6 +79,13 @@
       Remember to set permissions or umask to prevent readability of
       unencrypted files by other users.
     </para>
+    <para>
+      <command>chpasswd</command> does not use PAM to update the passwords.
+      Thus, It only updates the passwords from the
+      <filename>/etc/passwd</filename> and <filename>/etc/shadow</filename>
+      databases, and does not support the various checks provided by PAM
+      modules.
+    </para>
   </refsect1>
 
   <refsect1 id='see_also'>