diff --git a/chapter06/pkg-config.xml b/chapter06/pkg-config.xml
index c2cf4149f..13a98b396 100644
--- a/chapter06/pkg-config.xml
+++ b/chapter06/pkg-config.xml
@@ -51,7 +51,8 @@
 
     <para>Fix a problem with one of Pkg-config's tests:</para>
 
-<screen><userinput remap="pre">sed -i -e '/!done/i/   longArg = NULL;' popt/popt.c</userinput></screen>
+<screen><userinput remap="pre">sed -i -e '/!done/a\
+        longArg = NULL;' popt/popt.c</userinput></screen>
 
     <para>Prepare Pkg-config for compilation:</para>