When I use
C-f to find a file in Spacemacs, how can I use
<backspace> to navigate to the parent folder?
This is the default behavior if using the Ivy completion engine.
Assuming you are using Helm (the default for Spacemacs) for your completion engine, there is a command
helm-find-files-up-one-level which is bound to
C-l in the
helm-find-files-map. If you want to bind your backspace key to that function you can do this:
(define-key helm-find-files-map (kbd "<backspace>") 'helm-find-files-up-one-level)
You can put this into your
dotspacemacs/user-config section and re-evaluate your init file, or just evaluate it in the
*scratch* buffer to try it out first.