diff --git a/functions/exec.xml b/functions/exec.xml
index 156d0d599d..d4ebef6307 100644
--- a/functions/exec.xml
+++ b/functions/exec.xml
@@ -2,6 +2,15 @@
   <title>Program Execution functions</title>
   <titleabbrev>Program Execution</titleabbrev>
 
+  <partintro>
+   <simpara>
+    Those functions provides means to executes commands on the
+    system itself, and means secure such commands. Those functions
+    are also closely related to the 
+    <link linkend="language.operators.execution">backtick operator</link>.
+   </simpara>
+  </partintro>
+
   <refentry id="function.escapeshellarg">
    <refnamediv>
     <refname>escapeshellarg</refname>