Change Emacs Default Coding System

Question

My problem stems from Emacs inserting the coding system headers into source files containing non-ascii characters:

# -*- coding: utf-8 -*- 

My coworkers do not like these headers being checked into our repositories. I don't want them inserted into my files because Emacs automatically detects that the file should be UTF-8 regardless so there doesn't seem to be any benefit to anyone.

I would like to simply set Emacs to use UTF-8 automatically for all files, yet it seems to disagree with this idea. In an effort to fix this, I've added the following to my .emacs:

(prefer-coding-system 'utf-8) (setq coding-system-for-read 'utf-8) (setq coding-system-for-write 'utf-8) 

This does not seem to solve my problem. Emacs still inserts the coding-system headers into my files. Anyone have any ideas?

EDIT:

I think this problem is specifically related to ruby-mode. I still can't turn it off though.

Answer 1

This works for me:

(setq ruby-insert-encoding-magic-comment nil) 

As suggested here

I believe you're correct that it only happens in ruby-mode. It seems ruby-mode is trying to be helpful by adding the line, which makes Ruby detect the source file encoding automatically.