How do I detect return/enter key pressed in text input?

I would like the player to enter text in a text input object called txtCmd.

When the player presses the Enter (or Return) key, I would like to append the text from txtCmd to a text object called txtOut, clear the text in txtCmd and set focus on txtCmd.

Here is what I have so far, but it does not work:

I'm guessing the problem is that "newline" can be used for output, but is not the correct way to designate the value of the Return key in a string?

Thank you for that. I did realize afterwards that I was overcomplicating things, and that I needed to create a keyboard object. It is working well now.