(defun shell-command-on-region-or-line ()
  "Run selected text in a terminal or use the current line."
  (interactive)
  (shell-command
   (concat
    "gnome-terminal -e "
    (if (use-region-p)
        ;; current selection
        (buffer-substring (region-beginning) (region-end))
      ;; current line
      (thing-at-point 'line t)))))

;; Execute text in a terminal, no questions! (ctrl-alt-shift-enter to avoid accidents!)
(global-set-key (kbd "<c-m-s-return>") 'term-shell-command-on-region-or-line)