I'm used to write a ~ character by pressing Alt+N on Mac OS X. This does not work in Emacs. Alt+N key seems to be bind to the command history. So my question is how to write a ~ character in Emacs on Mac OS X?
EDIT: I'm using Aquamacs.
You could always open the 'character viewer', select 'Punctuation', find '~' (tilde), and then double click it. That will insert it at the Emacs point. (The 'character viewer' is readily accessible after checking 'Show Keyboard & Character Viewers in menu bar' from the Keyboard pane in the System Preferences window.)
You could also define an emacs-lisp function as:
(defun tilde () (interactive) (insert "~"))
and then invoke it with M-x tilde
to insert a tilde. Could then assign that function to the key combo of your choice as
(global-set-key "\M-\C-!" 'tilde) ;; you choose the combo
and add all this to your 'emacs init' file.