Add prelude-update command

README.md

@@ -101,6 +101,8 @@ $ git pull
 The `path/to/prelude/installation` is usually `~/.emacs.d` (at least
 on Unix systems).
 
+Alternatively you can run <kbd>M-x prelude-update</kbd> from Emacs itself.
+
 It's generally a good idea to stop Emacs before you do the update. The
 next time Prelude starts it will install any new dependencies (if
 there are such).

core/prelude-core.el

@@ -327,5 +327,14 @@ Doesn't mess with special buffers."
   (exchange-point-and-mark)
   (deactivate-mark nil))
 
+(defun prelude-update ()
+  "Update Prelude to its latest version."
+  (interactive)
+  (when (y-or-n-p "Do you want to update Prelude?")
+    (message "Updating Prelude...")
+    (cd prelude-dir)
+    (shell-command "git pull")
+    (message "Update finished. Restart Emacs to complete the process.")))
+
 (provide 'prelude-core)
 ;;; prelude-core.el ends here