To get a process buffer an eshell buffer I thought I used to be able to run:

(get-buffer-process (current-buffer))

In Emacs 25 this no longer works. Specifically "GNU Emacs (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8) of 2015-11-30"

Here is what I do. I start an eshell with M-x eshell. Then with that as the only window or buffer around I run

M-x eval

Eval: (get-buffer-process (current-buffer))

And the result is nil.

I am using this in the code for realgud, an emacs front-end to various debuggers. It needs to interact with the debugger like see if the debugger is running or has terminated, send commands to it and run hooks when output appears.

How would I do this?

  • 1
    Erm, what process are you expecting to find in an eshell buffer? I'm not an eshell user but, as far as I understand, one of the defining features of eshell is that there isn't an external process; and I can only presume this has always been the case.
    – phils
    Commented May 29, 2016 at 9:39
  • 1
    @phils You get the process of the program started in the eshell-buffer. But, that works fine for me with emacs 25.1.50.
    – Tobias
    Commented May 29, 2016 at 16:10
  • @Tobias Hmm. I am using GNU Emacs (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8) of 2015-11-30 and I am getting nil back. I'll revise the question to be more detailed about this.
    – rocky
    Commented May 29, 2016 at 20:06
  • 1
    Please see that eshell-session. (Note: It is a link to pastebin.com.) The first get-buffer-process returns nil, so nothing is shown. The second get-buffer-process returns the started xterm which is shown in the eshell-buffer. Emacs-version is also shown in this buffer.
    – Tobias
    Commented May 29, 2016 at 21:34
  • 1
    @Tobias if you post your comment as an answer I'll accept it. This solves my problem or rather confusion.
    – rocky
    Commented May 30, 2016 at 0:53

1 Answer 1


Eshell has not a process-id of its own. It is solely running on the base of emacs-lisp functions within emacs.

Nevertheless, you can start processes from an eshell buffer. The eshell buffer becomes the process-buffer for the started processes.

The following eshell session shows what is going on with processes in the eshell buffer.

Welcome to the Emacs shell

~ $ emacs-version 
GNU Emacs 24.5.1 (x86_64-unknown-cygwin, GTK+ Version 3.14.13)
 of 2015-06-23 on desktop-new
~ $ get-buffer-process (current-buffer)
~ $ /usr/bin/xterm &
[xterm<1>] 5168
~ $ get-buffer-process (current-buffer)
#<process xterm<1>>
~ $ /usr/local/bin/xpdf.exe &
[xpdf.exe] 6464
~ $ get-buffer-process (current-buffer)
#<process xpdf.exe>
~ $ process-buffer (get-process "xpdf.exe")
#<buffer *eshell*>
~ $ process-buffer (get-process "xterm<1>")
#<buffer *eshell*>
~ $ remove-if-not #'(lambda (proc) (equal (process-buffer proc) (current-buffer))) (process-list)
(#<process xpdf.exe> #<process xterm<1>>)

Note, that I have deleted some lines that may only cause confusion (e.g., font messages for the started processes).

Side note: It is rather interesting that both started background processes have the same eshell buffer as process buffer, i.e., the process of a process buffer is not unique. It looks like get-buffer-process gets only the last started process for the buffer.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.