Enhancement: From command prompt, add ability to toggle between the last issued command and an empty prompt

[tonedef71]

Sometimes when I type the cursor up key from the command prompt, I change my mind (the last entered command is not what I wanted).

When that happens, I can either hit the enter key to re-submit that last entered command, or I can hit the escape key to cancel, with the caveat that the Escape mechanism will be invoked (i.e. "Escape" is displayed and the prompt is advanced a couple of lines).

As an alternative, I would like to be able to simply type the cursor up key again to get back to the empty > prompt. Typing the cursor key multiple times could alternate between displaying the empty prompt or the last command entered.