emacs-custom file get overwritten

Question

In my init.el, I have the following line

(setq custom-file (expand-file-name "custom.el" user-emacs-directory))

which is supposed to set the file custom.el into .emacs.d config folder for getting all customization tidy. Over the years, emacs populated this file with various things.

I ran customization with M-x customize-variable and made some change and saved them. Afterwards, I discovered that emacs added the new custom into custom.el, overwriting the previous version of the file.

What's the mistake? Should I put (load custom-file) after the line above? Can this be the problem?

Answer 1

You used M-x customize-variable, edited the option value, and then saved it. When you save your changes they're written to your custom-file (or your init file, if you have no custom-file defined). So yes, it's normal that custom-file was overwritten.

Yes, in your init file, somewhere after you define the value of option custom-file, you need to load that file, if you want Emacs to recognize its customizations.

And it's generally better to use customize-save-variable or customize-set-variable than just setq, to change the value of a user option. It's not critical here, but it's a good habit to have.

For example, in your init file:

;; Possibly some stuff...

(customize-save-variable 'custom-file  (expand-file-name "custom.el" user-emacs-directory))

;; Possibly some other stuff...

(load-file custom-file)

;; Possibly some other stuff...