which means that backspace has already been mapped to C-d (that's why I
suspected this required some sort of keymap wizardry). While I could
live with C-d and Backspace both meaning delete-backward-char,
I'd really rather have C-d continue to mean "delete forward" like it
ought to.
Hm... you got me there. It sounds like maybe there's a site file
being loaded (in which case you can try the command line option
--no-site-file when you start Emacs, to the annoyance of your
sysadmins) *or* maybe you've just had some bad luck at the xmodmap
level if it is your own system. In any event, you can try changing
the behavior of the backspace key around using xmodmap (the analogue
of `global-set-key') and xev (the analogue of the help and command
history commands I showed you). See the man pages.
2) your syntax doesn't work in my version: If I try
(global-set-key "^d" 'backward-delete-char-untabify)
I get an initialization error "Key sequence ^ d uses invalid prefix
characters"
Did you copy the string from the *Command History* buffer? You don't
want an asciicircum and a "d" -- you want the "control d character".
You can insert this character without going through the
help/command-history hoops just by pressing C-q C-d.