Omitting Git-ignored files in Emacs dired

Adding the following snippet to your .emacs file will cause Emacs’ dired mode to omit all files ignored by Git. This only works if you have dired-omit-mode on, which is ordinarily bound to Meta-o.

The code

Here is the code you would add to your .emacs file:

(add-hook ‘dired-load-hook #’(lambda nil (load “dired-x” t)))

(eval-after-load “dired-x”
     (defvar dired-omit-regexp-orig (symbol-function ‘dired-omit-regexp))

     (defun dired-omit-regexp ()
       (let ((file (expand-file-name “.git”))
         (while (and (not (file-exists-p file))
                       (setq parent-dir
                               (file-name-directory file))))
                       ;; Give up if we are already at the root dir.
                       (not (string= (file-name-directory file)
           ;; Move up to the parent dir and try again.
           (setq file (expand-file-name “.git” parent-dir)))
         ;; If we found a change log in a parent, use that.
         (if (file-exists-p file)
             (let ((regexp (funcall dired-omit-regexp-orig)))
               (assert (stringp regexp))
                (if (> (length regexp) 0)
                    “\\|” “”)
                 #’(lambda (str)
                     (concat “^”
                              (substring str 13
                                         (if (= ?/ (aref str (1- (length str))))
                                             (1- (length str))
                 (split-string (shell-command-to-string
                                “git clean -d -x -n”)
                               “\n” t)
           (funcall dired-omit-regexp-orig))))))

A note to fellow Emacs coders: I tried writing this as a piece of defadvice, rather than hijacking the definition of dired-omit-regexp, but for some reason it never called this function.