diff --git a/en_US.ISO8859-1/books/porters-handbook/pkg-files/chapter.xml b/en_US.ISO8859-1/books/porters-handbook/pkg-files/chapter.xml
index 38655dacda..f4ae15e2eb 100644
--- a/en_US.ISO8859-1/books/porters-handbook/pkg-files/chapter.xml
+++ b/en_US.ISO8859-1/books/porters-handbook/pkg-files/chapter.xml
@@ -182,6 +182,9 @@ Always displayed
 EOM
 }
 ]</programlisting>
+
+	<para>The here document delimiter (<literal>EOM</literal>
+	  here) must be uppercase.</para>
       </tip>
 
       <warning>