Question

How can I set Emacs gdb so that it shows the most recent command when I press arrow-up?

In the Emacs gdb it will just go one line up in the buffer.

I know you can always just search backwards in the buffer and select a recent command there, but getting the command directly with arrow-up would be more convenient.

Answer 1

C-h B tell me that C-up is bound to comint-previous-input whose documentation is

Cycle backwards through input history, saving input.

One could rebind this to up (and down for symmetry) with:

(eval-after-load "gud"
  '(progn 
     (define-key gud-mode-map (kbd "<up>") 'comint-previous-input)
     (define-key gud-mode-map (kbd "<down>") 'comint-next-input)))