diff --git a/chapter06/zlib-inst.xml b/chapter06/zlib-inst.xml
index 013acda72..be9843265 100644
--- a/chapter06/zlib-inst.xml
+++ b/chapter06/zlib-inst.xml
@@ -7,7 +7,7 @@
 that, though difficult to take advantage of, should be taken care of. Do
 so by applying this patch:</para>
 
-<para><screen><userinput>patch -Np1 -i ../zlib-&zlib-patch-version;</userinput></screen></para>
+<para><screen><userinput>patch -Np1 -i ../zlib-&zlib-patch-version;.patch</userinput></screen></para>
 
 <para>Prepare Zlib to be compiled:</para>