Try to put a better example of EscapeShellCmd usage

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@32024 c90b9560-bf6c-de11-be94-00142212c4b1

functions/exec.xml

@@ -65,7 +65,10 @@ system("ls ".EscapeShellArg($dir))
     <para>
      <informalexample>
       <programlisting role="php">
-system(EscapeShellCmd($cmd))
+$e = EscapeShellCmd($userinput);
+system("echo $e"); // here we don't care if $e has spaces
+$f = EscapeShellCmd($filename);
+system("touch \"/tmp/$f\"; ls -l \"/tmp/$f\""); // and here we do, so we use quotes
       </programlisting>
      </informalexample>
     </para>