How to redefine prefix key in org mode?

Question

I have rebound C-u to another function, and try to use C-j for the prefix, but now it seems I cannot use the prefix in org-mode. It does seem to work in other modes though.

; This is the relevant part of my current config (I think)
(global-set-key "\C-j" 'universal-argument)
(define-key universal-argument-map "\C-j" 'universal-argument-more)
(define-key universal-argument-map "\C-u" nil)
(define-key global-map "\C-u" nil)

(use-package org
  :bind
  (:map org-mode-map
        ("C-e" . next-line))
  )

How can I make C-j the prefix in org-mode?

Answer 1

Your code will work for any mode that doesn't bind C-j for some purpose. orgmode binds C-j to org-return-indent in the org-mode keymap. The major-mode keymap takes precedence over the global keymap, so your modifications have no effect.

To make this work in org-mode, you'll need to bind C-j specifically in the orgmode keymap:

(define-key org-mode-map "\C-j" 'universal-argument)

You will run into the same problem in any mode that uses C-j for something. You might find some useful ideas in this answer.