.spacemacs.el

  (add-hook 'nrepl-connected-hook
            (lambda ()
              (require 'ansi-color)
              (with-current-buffer nrepl-server-buffer
                (linum-mode)
                (ansi-color-apply-on-region (point-min) (point-max))
                (add-hook 'after-change-functions
                          (lambda (begin end length)
                            (ansi-color-apply-on-region begin end))
                          nil
                          t))))