To protect newbie users from lossage, some Emacs commands are disabled by default due to their potentially destructive nature. When one tries to execute such a command, Emacs will ask you if you really want to do that and offer to un-disable it by putting a form like below in your .emacs:

    (put 'some-disabled-command 'disabled nil)

To enable all disabled commands in one fell swoop, put this in .emacs (not recommended for newbies):

    (setq disabled-command-function nil)

In older versions of Emacs, disabled-command-hook is used in place of disabled-command-function.

Another way to deal with disabled commands is to automatically enable them on the fly.

    ;; We hook up the enable-me using setq instead of add-hook. That's because the
    ;; add-hook would cause the original hook to come after enable-me. Instead we
    ;; want only enable-me to execute.
    ;; Thanks to Roland McGrath.
    (defun enable-me (&rest args)
      "Called when a disabled command is executed.
    Enable it and reexecute it."
      (put this-command 'disabled nil)
      (message "You typed %s.  %s was disabled.  It ain't no more."
               (key-description (this-command-keys)) this-command)
      (sit-for 0)
      (call-interactively this-command))
    (setq disabled-command-hook 'enable-me)

Alternatively, if you want to be told which commands were disabled (which are therefore likely to be powerful and interesting), you can use this function:

    (defun enable-all-commands ()
      "Enable all commands, reporting on which were disabled."
      (with-output-to-temp-buffer "*Commands that were disabled*"
          (lambda (symbol)
            (when (get symbol 'disabled)
              (put symbol 'disabled nil)
              (prin1 symbol)
              (princ "\n")))))))

If you use a separate custom file and want Emacs to place its disable/enable forms there instead of in your init file, you can use the following advice:

    (defadvice en/disable-command (around put-in-custom-file activate)
      "Put declarations in `custom-file'."
      (let ((user-init-file custom-file))