untabify on save

init.el

@@ -43,8 +43,13 @@
 (scroll-bar-mode -1)
 (global-hl-line-mode 1)
 
+(defun hgh/untabify-buffer ()
+  (interactive)
+  (untabify (region-beginning) (region-end) nil))
+
 (add-hook 'compilation-filter-hook 'ansi-color-compilation-filter)
 (add-hook 'before-save-hook 'delete-trailing-whitespace)
+(add-hook 'before-save-hook 'hgh/untabify-buffer)
 
 (if (file-exists-p custom-file)
     (load-file custom-file))