In the spirit of tmtowtdi (including using other tools besides perl), here's yet another way. i use an emacs macro -- if you use emacs, you can add this to your emacs profile:

(defun dos-unix ()
  (interactive)
  (goto-char (point-min))
  (while (search-forward "\r" nil t) (replace-match "")))
(defun unix-dos ()
  (interactive)
  (goto-char (point-min))
  (while (search-forward "\n" nil t) (replace-match "\r\n")))
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Since I have to work with a lot of code coming in from and going back out to Windows machines, I find this easier than a one-liner. To use it is a trivial matter of calling M-x dos-unix or M-x unix-dos.

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