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(efaq)Backspace invokes help

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Why does the <Backspace> key invoke help?
=========================================

   The <Backspace> key (on most keyboards) generates ASCII code 8.
`C-h' sends the same code.  In Emacs by default `C-h' invokes
help-command.  This is intended to be easy to remember since the first
letter of `help' is `h'.  The easiest solution to this problem is to
use `C-h' (and <Backspace>) for help and <DEL> (the <Delete> key) for
deleting the previous character.

   For many people this solution may be problematic:

   * They normally use <Backspace> outside of Emacs for deleting the
     previous character.  This can be solved by making <DEL> the command
     for deleting the previous character outside of Emacs.  On many Unix
     systems, this command will remap <DEL>:

          stty erase `^?'

   * The user may prefer the <Backspace> key for deleting the previous
     character because it is more conveniently located on their
     keyboard or because they don't even have a separate <Delete> key.
     In this case, the <Backspace> key should be made to behave like
     <Delete>.  There are several methods.

        - Some terminals (e.g., VT3## terminals) and terminal emulators
          (e.g., TeraTerm) allow the character generated by the
          <Backspace> key to be changed from a setup menu.

        - You may be able to get a keyboard that is completely
          programmable, or a terminal emulator that supports remapping
          of any key to any other key.

        - With Emacs 21.1 and later, you can control the effect of the
          <Backspace> and <Delete> keys, on both dumb terminals and a
          windowed displays, by customizing the option
          `normal-erase-is-backspace-mode', or by invoking `M-x
          normal-erase-is-backspace'.  See the documentation of these
          symbols (Note: Emacs Lisp documentation) for more info.

        - It is possible to swap the <Backspace> and <DEL> keys inside
          Emacs:

               (keyboard-translate ?\C-h ?\C-?)

          This is the recommended method of forcing <Backspace> to act
          as <DEL>, because it works even in modes which bind <DEL> to
          something other than `delete-backward-char'.

          Similarly, you could remap <DEL> to act as `C-d', which by
          default deletes forward:

               (keyboard-translate ?\C-? ?\C-d)

          Note: Swapping keys, for further details about
          `keyboard-translate'.

        - Another approach is to switch key bindings and put help on
          `C-x h' instead:

               (global-set-key "\C-h" 'delete-backward-char)
               
               ;;; overrides mark-whole-buffer
               (global-set-key "\C-xh" 'help-command)

          This method is not recommended, though: it only solves the
          problem for those modes which bind <DEL> to
          `delete-backward-char'.  Modes which bind <DEL> to something
          else, such as `view-mode', will not work as you expect when
          you press the <Backspace> key.  For this reason, we recommend
          the the `keyboard-translate' method, shown above.

          Other popular key bindings for help are `M-?' and `C-x ?'.

     Don't try to bind <DEL> to `help-command', because there are many
     modes that have local bindings of <DEL> that will interfere.


   When Emacs 21 or later runs on a windowed display, it binds the
<Delete> key to a command which deletes the character at point, to make
Emacs more consistent with keyboard operation on these systems.

   For more information about troubleshooting this problem, see Note:
If <DEL> Fails to Delete.