My basic emacs setting.

init.el

(package-initialize)

(setq auto-save-default nil)

;; Not make backup files
(setq make-backup-files nil)

;; Set language environment
(set-language-environment "UTF-8")

;; Show line number
(global-linum-mode t)
;; Custom line number style
(setq linum-format "%4d  ")

;; set tab size 4
(setq default-tab-width 4)

;; prevent auto indentation
;;(when (fboundp 'electric-indent-mode) (electric-indent-mode -1))


(global-set-key (kbd "<backtab>") 'un-indent-by-removing-4-spaces)
(defun un-indent-by-removing-4-spaces ()
  "remove 4 spaces from beginning of of line"
  (interactive)
  (save-excursion
	(save-match-data
	  (beginning-of-line)
	  ;; get rid of tabs at beginning of line
	  (when (looking-at "^\\s-+")
		(untabify (match-beginning 0) (match-end 0)))
	  (when (looking-at "^    ")
	    (replace-match "")))))