** passing values through to STDIN of shell code blocks
#+results: square-table
| 1 | 2 | 3 |
| 4 | 5 | 6 |
| 7 | 8 | 9 |

#+source: first-col
#+begin_src sh :stdin square-table
  awk '{print $1}'
#+end_src

#+begin_src sh :stdin first-col
  sed 's/4/middle/g'
#+end_src

#+results:
|      1 |
| middle |
|      7 |