diff --git a/chapter05/patch-exp.xml b/chapter05/patch-exp.xml
index 82a5489e8..12b36a78a 100644
--- a/chapter05/patch-exp.xml
+++ b/chapter05/patch-exp.xml
@@ -1,8 +1,8 @@
 <sect2>
 <title>Command explanations</title>
 
-<para><userinput>CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE": </userinput>
-Adding <userinput>-D_GNU_SOURCE</userinput> command before
+<para><userinput>CPPFLAGS=-D_GNU_SOURCE: </userinput>
+Adding <userinput>-D_GNU_SOURCE</userinput> to CPPFLAGS command before
 we configure patch fixes installation of the package on PPC and m68k
 platforms (that we know of).  It also doesn't hurt compilation on other
 platforms (such as x86) so we do it by default.</para>