这是我的设置：

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ENCODING ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; C-h C RET
;; M-x describe-current-coding-system

(add-to-list 'file-coding-system-alist '("\\.tex" . utf-8-unix) )
(add-to-list 'file-coding-system-alist '("\\.txt" . utf-8-unix) )
(add-to-list 'file-coding-system-alist '("\\.el" . utf-8-unix) )
(add-to-list 'file-coding-system-alist '("\\.scratch" . utf-8-unix) )
(add-to-list 'file-coding-system-alist '("user_prefs" . utf-8-unix) )

(add-to-list 'process-coding-system-alist '("\\.txt" . utf-8-unix) )

(add-to-list 'network-coding-system-alist '("\\.txt" . utf-8-unix) )

(prefer-coding-system 'utf-8-unix)
(set-default-coding-systems 'utf-8-unix)
(set-terminal-coding-system 'utf-8-unix)
(set-keyboard-coding-system 'utf-8-unix)
(set-selection-coding-system 'utf-8-unix)
(setq-default buffer-file-coding-system 'utf-8-unix)

;; Treat clipboard input as UTF-8 string first; compound text next, etc.
(setq x-select-request-type '(UTF8_STRING COMPOUND_TEXT TEXT STRING))

;; mnemonic for utf-8 is "U", which is defined in the mule.el
(setq eol-mnemonic-dos ":CRLF")
(setq eol-mnemonic-mac ":CR")
(setq eol-mnemonic-undecided ":?")
(setq eol-mnemonic-unix ":LF")

(defalias 'read-buffer-file-coding-system 'lawlist-read-buffer-file-coding-system)
(defun lawlist-read-buffer-file-coding-system ()
  (let* ((bcss (find-coding-systems-region (point-min) (point-max)))
         (css-table
          (unless (equal bcss '(undecided))
            (append '("dos" "unix" "mac")
                    (delq nil (mapcar (lambda (cs)
                                        (if (memq (coding-system-base cs) bcss)
                                            (symbol-name cs)))
                                      coding-system-list)))))
         (combined-table
          (if css-table
              (completion-table-in-turn css-table coding-system-alist)
            coding-system-alist))
         (auto-cs
          (unless find-file-literally
            (save-excursion
              (save-restriction
                (widen)
                (goto-char (point-min))
                (funcall set-auto-coding-function
                         (or buffer-file-name "") (buffer-size))))))
         (preferred 'utf-8-unix)
         (default 'utf-8-unix)
         (completion-ignore-case t)
         (completion-pcm--delim-wild-regex ; Let "u8" complete to "utf-8".
          (concat completion-pcm--delim-wild-regex
                  "\\|\\([[:alpha:]]\\)[[:digit:]]"))
         (cs (completing-read
              (format "Coding system for saving file (default %s): " default)
              combined-table
              nil t nil 'coding-system-history
              (if default (symbol-name default)))))
    (unless (zerop (length cs)) (intern cs))))