How do I instruct emacs to use 4 spaces instead of the tab character for all indentation?

Question

What do I put in my .emacs file to use four spaces instead of the tab character for all indentation?

Answer 1

This behavior is controlled by the variable indent-tabs-mode. Put:

(setq-default indent-tabs-mode nil)

in your .emacs to use spaces.

Answer 2

Please note that tabs and indentation in emacs is a more complicated subject than most people anticipate. I strongly recommend reading up on the subject at the Emacs Wiki, because the above information is far from comprehensive.