http://wikemacs.org/wiki/Emacs_Lisp_in_15_minutes

elisp-in-15-min.el

(+ 1 (+ 3 4))
(setq name "weaming")
(defun hello (name) (insert "Hello, " name))
(hello "weaming")
(switch-to-buffer-other-window "*test*")

(progn
  (switch-to-buffer-other-window "*test*")
  (erase-buffer)
  (hello "you")
  (other-window 1)
  )
 
(let ((local-name "Garden"))
  (switch-to-buffer-other-window "*test*")
  (erase-buffer)
  (greeting local-name)
  (other-window 1)
  )

(defun greeting (from-name)
  (let ((your-name (read-from-minibuffer "Enter your name: ")))
  (insert (format "Hello, %s!\n\nI am %s." your-name from-name ))
  ))


;; list
(setq list-of-names '("A" "B" "C"))
(greeting (car list-of-names))
(insert (cdr list-of-names))
(push "D" list-of-names)
(push "E" list-of-names)
(mapcar 'hello list-of-names) 

(defun greeting ()
    (switch-to-buffer-other-window "*test*")
    (erase-buffer)
    (mapcar 'hello list-of-names)
    (other-window 1))

(greeting)

(defun replace-hello-by-bonjour ()
  (switch-to-buffer-other-window "*test*")
  (goto-char (point-min))
  (while (search-forward "Hello")
    (replace-match "Bonjour"))
  (other-window 1))

(replace-hello-by-bonjour)


(defun replace-text (from to)
  (switch-to-buffer-other-window "*test*")
  (goto-char (point-min))
  (while (search-forward from)
    (replace-match to))
  (other-window 1))

(replace-text "Bonjour" "Hello")
(replace-text "Hello" "Bonjour")

(defun boldify-text ()
  (switch-to-buffer-other-window "*test*")
  (goto-char (point-min))
  (while (re-search-forward "Bonjour \\(.+\\)!" nil t)
    (add-text-properties (match-beginning 1)
      (match-end 1)
      (list 'face 'bold)))
  (other-window 1))

(boldify-text)