remap Enter in normal mode but not in command line

Question

I have remapped the Enter key in normal mode to add a new line:

nnoremap <CR> o<Esc>k

Works great, but now in the command line (entered by q:) this command add new line either, but I would like to leave it in default mode, this is execute the selected command from history.

So the question is, how can I remap a key in normal mode, but not in command line?

Answer 1

This autocommand does what you want:

augroup commandlinewindow
  autocmd!
  autocmd CmdwinEnter * nnoremap <buffer> <CR> <CR>
augroup END

It's the "command-line window", by the way, not the "command line".

Answer 2

In addition to command-line window you'll almost certainly need this one. For quickfix window:

autocmd BufReadPost quickfix nnoremap <buffer> <CR> <CR>