Index: en_US.ISO8859-1/books/porters-handbook/slow-porting/chapter.xml
===================================================================
--- en_US.ISO8859-1/books/porters-handbook/slow-porting/chapter.xml
+++ en_US.ISO8859-1/books/porters-handbook/slow-porting/chapter.xml
@@ -294,12 +294,14 @@
 	</listitem>
 
 	<listitem>
-	  <para>When creating names for patch files, replace slashes
-	    (<literal>/</literal>) with two underscores
-	    (<literal>__</literal>).  For example, to patch a file
+	  <para>When creating names for patch files, replace each
+	    underscore (<literal>_</literal>) with two underscores
+	    (<literal>__</literal>) and each slashes
+	    (<literal>/</literal>) with one underscore
+	    (<literal>_</literal>).  For example, to patch a file
 	    named <filename>src/freeglut_joystick.c</filename>, name
 	    the corresponding patch
-	    <filename>patch-src__freeglut_joystick.c</filename>.  Do
+	    <filename>patch-src_freeglut__joystick.c</filename>.  Do
 	    not name patches like <filename>patch-aa</filename> or
 	    <filename>patch-ab</filename>.  Always use the path and
 	    file name in patch names.  Using <command>make
@@ -318,7 +320,7 @@
 	  <para>Only use characters <literal>[-+._a-zA-Z0-9]</literal>
 	    for naming patches.  In particular, <emphasis>do not use
 	      <literal>::</literal> as a path separator,</emphasis>
-	    use <literal>__</literal> instead.</para>
+	    use <literal>_</literal> instead.</para>
 	</listitem>
       </itemizedlist>