** silent results in org but not in export
   :PROPERTIES:
   :DATE:     2011-09-06
   :END:
The results of the following code block will not be inserted during
interactive evaluation but will during export.

#+begin_src sh :results (if org-current-export-file "replace" "silent") :exports both
  echo  "I want to see this in HTML/PDF, but not in Org"
#+end_src