comint-copy-old-input). This is useful if you move point back to a previous command. After you copy the command, you can submit the copy as input with <RET>. If you wish, you can edit the copy before resubmitting it. If you use this command on an output line, it copies that line to the end of the buffer.
nil(the default), copy the old input command that you click on, inserting the copy at the end of the buffer (
nil, or if the click is not over old input, just yank as usual.
Moving to a previous input and then copying it with C-c <RET> or Mouse-2 produces the same results—the same buffer contents—that you would get by using M-p enough times to fetch that previous input from the history list. However, C-c <RET> copies the text from the buffer, which can be different from what is in the history list if you edit the input text in the buffer after it has been sent.