Googled it and there is already (global-undo-tree-mode) (setq undo-tree-auto-save-history t) (setq undo-tree-history-directory-alist '(("." . "~/.e

Googled it and there is already (global-undo-tree-mode) (setq undo-tree-auto-save-history t) (setq undo-tree-history-directory-alist '(("." . "~/.emacs.d/undo"))) I did not know that.