I activated the formatting on save in the init.el file uncommenting the following line

(format +onsave)  ; automated prettiness

But when I save a Python file, I get the following error message:

Error (before-save-hook): Error running hook "+format-buffer-h" because: (error You need the "black" command. You may be able to install it via "pip install black".)

I installed black with pip, as the message says, but I keep getting the same message.

I set the following settings for the Python black formatter (found it here):

;; package.el
(package! python-black)
;; config.el
(use-package! python-black
  :demand t
  :after python
  (add-hook! 'python-mode-hook #'python-black-on-save-mode)
  ;; Feel free to throw your own personal keybindings here
  (map! :leader :desc "Blacken Buffer" "m b b" #'python-black-buffer)
  (map! :leader :desc "Blacken Region" "m b r" #'python-black-region)
  (map! :leader :desc "Blacken Statement" "m b s" #'python-black-statement)

I did run doom sync after changing the settings, and it installed some packages, but I still get the same error when saving Python files.

I'm using Fedora 34, and installed black for Python 3.9. I also tried to install black for Python 2.7, but it's not supported anymore, so I was guessing that maybe Emacs is expecting black to be installed for Python 2.7, That's only a conjecture because I'm new to Emacs and don't know much about it.

Is there a way to make Python formatting work?

1 Answer 1


I just activated python and (format +onsave) only.
You must run doom/reload (SPC h r r) after doom sync.

Activate virtualenv with SPC : pyvenv-activate
Install black with python -m pip install black
Close open Python buffer and open again.

SPC b s to save buffer.
SPC c f to format buffer / region.

Run doom doctor to diagnose problems.

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