starter-kit-defuns.el

(defun untabify-buffer ()
  (interactive)
  (untabify (point-min) (point-max)))

(defun indent-buffer ()
  (interactive)
  (indent-region (point-min) (point-max)))

(defun cleanup-buffer ()
  "Perform a bunch of operations on the whitespace content of a buffer."
  (interactive)
  (indent-buffer)
  (untabify-buffer)
  (delete-trailing-whitespace))