code: def run_system_command(self, command):
          
          def wait_for_enter():
              """
              Create a sub application to wait for the enter key press.
              This has two advantages over using 'input'/'raw_input':
              - This will share the same input/output I/O.
              - This doesn't block the event loop.
              """
              from .shortcuts import create_prompt_application
  
              registry = Registry()
  
              @registry.add_binding(Keys.ControlJ)
              @registry.add_binding(Keys.ControlM)
              def _(event):
                  event.cli.set_return_value(None)
  
              application = create_prompt_application(
                  message='Press ENTER to continue...',
                  key_bindings_registry=registry)
              self.run_sub_application(application)
  
          def run():
              # Try to use the same input/output file descriptors as the one,
              # used to run this application.
              try:
                  input_fd = self.input.fileno()
              except AttributeError:
                  input_fd = sys.stdin.fileno()
              try:
                  output_fd = self.output.fileno()
              except AttributeError:
                  output_fd = sys.stdout.fileno()
  
              # Run sub process.
              # XXX: This will still block the event loop.
              p = Popen(command, shell=True,
                        stdin=input_fd, stdout=output_fd)
              p.wait()
  
              # Wait for the user to press enter.
              wait_for_enter()
  
          self.run_in_terminal(run)
docs: Run system command (While hiding the prompt. When finished, all the
          output will scroll above the prompt.)
  
          :param command: Shell command to be executed.