Emacs File Encoding FAQ

By Xah Lee. Date: . Last updated: .

This page is a tutorial on file and character encoding/decoding in emacs.

If you don't know what's encoding/decoding, see: Unicode Basics.

How to open a file with specific coding system?

Open it normally, then Alt+x revert-buffer-with-coding-system, then type a coding system. Press Tab to list possible ones.

How to set a encoding system for saving file?

Alt+x set-buffer-file-coding-system, then type the encoding system you want. Press Tab to see a list of possible values.

After you set a encoding system, you can save the file and it'll be saved in the new encoding system.

In a buffer, how to find out what encoding system was used to decode current file?

Check the value of the variable buffer-file-coding-system. You do that by Alt+x describe-variableCtrl+h v】.

emacs describe-coding-system
emacs describe-coding-system

How to find out what's the current coding system used for opening and saving files?

Alt+x describe-coding-system

How to permanently choose a encoding system in emacs for opening and saving?

Put this in your emacs init file:

;; UTF-8 as default encoding
(set-language-environment "UTF-8")

What encoding systems emacs supports?

Alt+x list-coding-systems

Is there a way to declare a file with a particular character encoding?

Yes. In the first line of your file, put -*- coding: utf-8 -*-. That way, each time emacs open the file, emacs will presume that the file is encoded in utf-8. The line can start with a comment character(s) of your language, such as “#”, “//”. This magic line is also adopted by Python.

(info "(emacs) File Variables")

Where can one read more about Unicode in emacs?

Unicode Basics

(info "(emacs) International")

Unicode Topic

  1. Unicode Basics
  2. Unicode Tutorial
  3. Emacs File Encoding FAQ
  4. Best Unicode Fonts for Programer
  5. Elisp: Unicode Representation in String
  6. Xah Math Input Mode
  7. Xah Unicode Browser Mode

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