;; if indent-tabs-mode is off, untabify before saving (add-hook 'write-file-hooks (lambda () (if (not indent-tabs-mode)

;; if indent-tabs-mode is off, untabify before saving (add-hook 'write-file-hooks (lambda () (if (not indent-tabs-mode) (untabify (point-min) (point-max))) nil)) is pretty sweet if you are lazy.