How can I convert a \'normal\' Git repository to a bare one?
The main difference seems to be:
in the normal Git repository, you have a .git
Your method looks like it would work; the file structure of a bare repository is just what is inside the .git directory. But I don't know if any of the files are actually changed, so if that fails, you can just do
git clone --bare /path/to/repo
You'll probably need to do it in a different directory to avoid a name conflict, and then you can just move it back to where you want. And you may need to change the config file to point to wherever your origin repo is.