(defun delete-trailing-whitespace ()
  "Delete all the trailing whitespace across the current buffer.
All whitespace after the last non-whitespace character in a line is deleted.
This respects narrowing, created by \\[narrow-to-region] and friends.
A formfeed is not considered whitespace by this function."
  (interactive "*")
  (save-match-data
    (save-excursion
      (goto-char (point-min))
      (let ((count 0))
        (while (re-search-forward "[ \t\r]+$" nil t)
          (replace-match "")(setq count (1+ count)))
        (message "Cleaned %d lines" count)))))