Emacs: Convert File Line Ending 💠

Here's emacs command that convert file line endings (Linux, Microsoft Windows, Mac OS 9), on current file, or marked files in dired in batch.

put this in your Emacs Init File:

(defun xah-change-file-line-ending-style (Files Style)
  "Change current file or `dired' marked file's newline convention.

When called in lisp, Style is one of 'unix 'dos 'mac or any of accepted emacs coding system. See `list-coding-systems'.

URL `http://xahlee.info/emacs/emacs/elisp_convert_line_ending.html'
Created: 2016-10-16
Version: 2023-10-29"
  (interactive
   (list
    (if (eq major-mode 'dired-mode)
        (dired-get-marked-files)
      (list buffer-file-name))
    (let ((completion-ignore-case t)
          (xmenu
           '(("Unix Linux MacOSX" . unix)
             ("Windows" . dos)
             ("MacOS9" . mac)))
          xstyle
          )
      (setq xstyle (completing-read "Line ending:" xmenu nil t nil nil (caar xmenu)))
      (cdr (assoc xstyle xmenu)))))
  (mapc
   (lambda (x) (xah-convert-file-coding-system x Style))
   Files))

(defun xah-convert-file-coding-system (Fpath CodingSystem)
  "Convert file's encoding.
 Fpath is full path to file.
 CodingSystem is one of 'unix 'dos 'mac or any of accepted emacs coding system. See `list-coding-systems'.

If the file is already opened, it is saved after this command.

URL `http://xahlee.info/emacs/emacs/elisp_convert_line_ending.html'
Created: 2015-07-24
Version: 2024-09-28"
  (let ((xbufferOpened-p (get-file-buffer Fpath)))
    (if xbufferOpened-p
        (with-current-buffer xbufferOpened-p
          (if (string-equal CodingSystem buffer-file-coding-system)
              nil
            (progn
              (set-buffer-file-coding-system CodingSystem)
              (save-buffer))))
      (with-temp-file Fpath
        (insert-file-contents Fpath)
        (if (string-equal CodingSystem buffer-file-coding-system)
            nil
          (set-buffer-file-coding-system CodingSystem))))))