environment: make bash.bashrc note more clear

Decorate usernames with XML labels.
Modify the command so it only applies to systems with bash.bashrc.
Correct the time point which we stop to use lfs user.
Tell the audience that bash.bashrc is useless on LFS.



git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11973 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter04/settingenviron.xml

@@ -157,17 +157,25 @@ EOF</userinput></screen>
 
      <para>Several commercial distributions add a non-documented instantiation
      of <filename>/etc/bash.bashrc</filename> to the initialization of
-     <command>bash</command>. This file has the potential to modify the lfs
+     <command>bash</command>. This file has the potential to modify the
+     <systemitem class="username">lfs</systemitem>
      user's envirnment in ways that can affect the building of critical LFS
-     packages. To make sure the lfs user's envronment is clean, check for the
+     packages. To make sure the <systemitem class="username">lfs</systemitem>
+     user's envronment is clean, check for the
      presence of <filename>/etc/bash.bashrc</filename> and, if present, move it
-     out of the way.  As the root user, run:</para>
+     out of the way.  As the <systemitem class="username">root</systemitem>
+     user, run:</para>
 
-     <screen role="nodump"><userinput>mv -v /etc/bash.bashrc /etc/bash.bashrc.NOUSE</userinput></screen> 
+     <screen role="nodump"><userinput>[ ! -e /etc/bash.bashrc ] || mv -v /etc/bash.bashrc /etc/bash.bashrc.NOUSE</userinput></screen> 
 
-     <para>After use of the lfs user is finished at the end of <xref
+     <para>After use of the lfs user is finished at the beginning of <xref
      linkend="chapter-chroot-temporary-tools"/>, you can restore
-     <filename>/etc/bash.bashrc</filename> (if desired).</para>
+	 <filename>/etc/bash.bashrc</filename> (if desired).</para>
+
+     <para>Note that the LFS Bash package we will build in
+     <xref linkend="ch-system-bash"/> is not configured to load or execute
+     <filename>/etc/bash.bashrc</filename>, so this file is useless on a
+     completed LFS system.</para>
   </important>
 
   <para>Finally, to have the environment fully prepared for building the