gistfile1.txt

(defun my-perltidy-command ()
  (concat "my-perltidy "
    (cond
      ((buffer-file-name) (file-truename buffer-file-name))
      (t ""))))

(defun perltidy-region ()
  "Run perltidy on the current region."
  (interactive)
  (save-excursion
    (shell-command-on-region (point) (mark) (my-perltidy-command) nil t)
    (cperl-mode)))

(defun perltidy-all ()
  "Run perltidy on the current region."
  (interactive)
  (let ((p (point)))
    (save-excursion
      (shell-command-on-region (point-min) (point-max) (my-perltidy-command) nil t)
      )
    (goto-char p)
    (cperl-mode)))