emacs - editing many files

gistfile.el

;; processing many files
;; depends on dired+

(defun on-dired-marked-files (f)
  (interactive "aFunction to call on each file: ")
  (dolist (file (diredp-get-files nil nil t t))
    (when (not (file-directory-p file))
        (find-file file)
        (funcall f))))

(add-hook 'dired-mode-hook
          (lambda () (define-key dired-mode-map
                       (kbd "C-c f") 'on-dired-marked-files)))

;; example edit function (depends on mark-multiple) 
(defun edit-with-client ()
  (interactive)
  (when (search-forward "with-client\ " nil t)

    (backward-word 2)
    (set-mark (point))
    (forward-word 2)
    (mc/mark-all-like-this)
    (backward-word)
    (insert-string "queued-")
    (paredit-forward)
    (kill-sexp)))