indent / unindent region of text in emacs, C/P from EmacsWiki

indent.el

(defun shift-text (distance)
  (if (use-region-p)
      (let ((mark (mark)))
        (save-excursion
          (indent-rigidly (region-beginning)
                          (region-end)
                          distance)
          (push-mark mark t t)
          (setq deactivate-mark nil)))
    (indent-rigidly (line-beginning-position)
                    (line-end-position)
                    distance)))

(defun shift-right (count)
  (interactive "p")
  (shift-text count))

(defun shift-left (count)
  (interactive "p")
  (shift-text (- count)))

(global-set-key (kbd "C-x >") (lambda () (interactive) (shift-right 4)))
(global-set-key (kbd "C-x <") (lambda () (interactive) (shift-left 4)))