Emacs - global hotkey to toggle read-only mode

w_for_writable.el

;; Wdired-mode
;;
;; (C-c C-c to commit changes)
;;
(define-key dired-mode-map (kbd "C-x C-q") 'wdired-change-to-wdired-mode) 

;; Wgrep-mode
;;
;; (C-c C-c to commit changes)
;;
(require 'wgrep)                                                      
(define-key grep-mode-map (kbd "C-x C-q") 'wgrep-change-to-wgrep-mode)

;; Occur-edit-mode
;;
;; (C-c C-c to commit changes)
;;
(define-key occur-mode-map (kbd "C-x C-q") 'occur-edit-mode)

;; Term-mode
;;
;; via http://joelmccracken.github.io/entries/switching-between-term-mode-and-line-mode-in-emacs-term/ 
;;                                                                                                     
(defun jnm/term-toggle-mode ()                                                                         
  "Toggles term between line mode and char mode"                                                       
  (interactive)                                                                                        
  (if (term-in-line-mode)                                                                              
      (term-char-mode)                                                                                 
    (term-line-mode)))                                                                                 
                                                                                                       
(define-key term-mode-map (kbd "C-x C-q") 'jnm/term-toggle-mode)                                       
(define-key term-raw-map  (kbd "C-x C-q") 'jnm/term-toggle-mode)