Weekly Emacs tip #6: highlight uncommitted changes: diff-hl

After enabling diff-hl-mode by Github user dgutov any lines with uncommitted changes in a (version controlled) file will be highlighted in the margin. In large files, for example, this makes it easy to spot the sections that you have edited.

Here is how I enable diff-hl-mode for all files:

;;;;;;;;;;;;;;;;;;;;
;; Enable diff-hl-mode (https://github.com/dgutov/diff-hl) to
;; highlight lines with uncommitted changes
(use-package diff-hl
  :after magit
  :init (global-diff-hl-mode)
  :custom
  ;; If working via Tramp is slow, try setting the following:
  ;; (diff-hl-disable-on-remote t)
  :hook
  ((magit-pre-refresh . diff-hl-magit-pre-refresh)
   (magit-post-refresh . diff-hl-magit-post-refresh))
  (vc-checkin . diff-hl-update)
  )

Note that if you don’t use Magit (yet…), the two lines from the :hook section that refer to it can be removed, as well as the :after line.

The project web site (https://github.com/dgutov/diff-hl) has some good screenshots that show what the result looks like, as well as more information on how to enable this in dired-mode so you can see which files have changed when browsing files and directories in dired.