Andreas Röhler [2013-06-06 10:16:22 +02:00] wrote:

> I'm looking for a command, which would replace character at point by
> its successor in alphabet.
>
> I.e. make B from A, C from B etc.

"Successor in alphabet" may vary between languages but if successor in
character codes suits you, it's very simple:

    (defun shift-char-after ()
      (interactive)
      (save-excursion
        (insert (1+ (char-after)))
        (delete-char 1)))