org-babel: capturing the output of a shell command that does not return

org-babel: capturing the output of a shell command that does not return

[garjola]

Hi,

I need to capture the output of a shell command run from a babel code block, but this command does not return. By that, I mean that the command prints some text to the terminal, but does not end (it launches a deamon). Something like this:

#+BEGIN_SRC bash
jupyter kernel 
#+END_SRC

When run in a terminal, the command outputs some text like:

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >
> [KernelApp] Starting kernel 'python3'                                                                >
> [KernelApp] Connection file: /run/user/1000/jupyter/kernel-8a5cf00c-182c-4212-9bbc-7aa6ec436b95.json >
> [KernelApp] To connect a client: --existing kernel-8a5cf00c-182c-4212-9bbc-7aa6ec436b95.json         >
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >

and sits there waiting for requests. I would like to capture the output to parse it. I need the name of the json file to pass it as a :session argument to subsequent code blocks like this:

#+BEGIN_SRC emacs-lisp
(setq org-babel-default-header-args
      (cons '(:session . "/run/user/1000/jupyter/kernel-8a5cf00c-182c-4212-9bbc-7aa6ec436b95.json")
            (assq-delete-all :session org-babel-default-header-args)))
#+END_SRC

#+BEGIN_SRC ipython :results output drawer :session "/run/user/1000/jupyter/kernel-8a5cf00c-182c-4212-9bbc-7aa6ec436b95.json"
print(2+2)
#+END_SRC

Maybe there is another way to run the shell command and extract the file name I need (in elisp?), but I don't know how.

I anybody could point me in the right direction, this would be very helpful.

Thank you.

G.

-- 

Re: org-babel: capturing the output of a shell command that does not return

[Grant Rettke]

On Wed, Sep 19, 2018 at 3:35 PM <garjola@garjola.net> wrote:
> Maybe there is another way to run the shell command and extract the file name I need (in elisp?), but I don't know how.

What if you start Emacs, have it create a temp file, then in a
separate terminal start Jupyter with stdout redirected to that file.

Is that in the right direction of what you are describing?