On Mon, May 22, 2017 at 2:11 PM R. Diez <rdiezmail-emacs@yahoo.de> wrote:

>
> Please copy me on the answer, as I am not subscribed to the list.
>

For future, all help questions can go to help-gnu-emacs@gnu.org

To answer your question, here is one way:

    (defun kill-matching-buffers-just-do-it ()
      "Kill buffers whose names match REGEXP, without asking."
      (interactive)
      (cl-letf (((symbol-function 'kill-buffer-ask) #'kill-buffer))
        (call-interactively #'kill-matching-buffers)))

-- 

Kaushal Modi