[O] data tables produced by shell source block

[Ken Mankoff]

The babel sh example here:
http://orgmode.org/worg/org-contrib/babel/intro.html#source-code-execution
 
says (and shows), "Babel automatically converts the output into an
Org-mode table.". When I run that same code 

#+name: directories
#+begin_src sh :results replace
  cd ~ && du -sc * |grep -v total
#+end_src

I do not get a table. Rather, I get the results in two columns and a
"#+begin_example"

#+RESULTS: directories
#+begin_example
<etc>

Can anyone provide a working example for generating a table in shell
mode that can then be used with Python code?

Thanks,

  -k.