No output from babel shell src block

[John Hendy <jw.hendy@gmail.com>]

Hello,


I've not used shell in babel much, and am confused. I was trying to
include diff output from a block in an analysis and it's not giving
any output.

As a test, I have a.txt which contains 1 and b.txt which contains 2,
with boths in ~/Desktop.

Manually:
$ cd ~/Desktop
$ diff a.txt b.txt
1c1
< 1
---
> 2

Org:
#+begin_src shell

cd ~/Desktop
diff a.txt b.txt

#+end_src

I get "Code block produced no output" with C-c C-c. If I replace the
diff line with =pwd=, it puts the current directory in the results
block (works as expected).

I've tried replace, append, output, raw, and value for :results, as
well as results and both for :exports. I've also tried using a #+name:
which gives me a results block for the output, but it's empty.

Am I missing something? Perhaps there's an analog for how some
programs need a print() of some kind for the results to show up? Then
again, I don't know why =pwd= works... There's no worg page for the
shell language (surprised me!).


Thanks,
John