added class attribute for filename tag containing a directory name

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@1673 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/shellutils-inst.xml

@@ -21,7 +21,7 @@ often used in shell scripts to evaluate conditions, but is more often
 encountered in the form of <command>[ condition ]</command>. These brackets 
 are built into the bash interpreter, but the FHS dictates that there should be a
 <filename>[</filename> binary. We create that in this way, while still in the
-<filename>/bin</filename> directory:</para>
+<filename class="directory">/bin</filename> directory:</para>
 
 <para><screen><userinput>cd /bin &amp;&amp;
 ln -sf test [</userinput></screen></para>