d.Z. wrote:
Thanks for helping everybody.

But actually I'm using Bourne shell on FreeBSD 6.1 just like the
Solaris in lab, and the FreeBSD is freshly installed, I have checked
.shrc and .profile, but nothing related to key bindings or stty's
there, so what I thought it should be is:

after I login -> [press backspace] -> ^H appears -> [press DEL] -> ^? appears
in emacs -> [press backspace] -> oops, help appears

stty can translate a small set of keystrokes into functions and gets used by the shell. In stty you can set the erase character to Ctrl-H. The shell uses the stty definitions for the keys.

For historical reasons emacs uses it's own keybindings and they don't work well with the default keystrokes emitted by the syscons driver in FreeBSD. In particular emacs want's Ctrl-H to start the help system, "H" for help... But, CTRL-H is also the default ASCII code sent by the Backspace key. That's why backspace works fine in your shell and brings up help in emacs. There are at least three solutions to this problem.

In the distant past some old terminals sent the ASCII code DEL (^? , or 0x7f) when the backspace key was pressed. Most modern terminals and terminal emulators can be setup to have this behaviour. In this case you can have stty use ^? as your erase character and have emacs respond to DEL by deleting the character before the point in the buffer. Then you can have FreeBSD send DEL when you press backspace by changing the keymap.

     $ man syscons
     $ man 1 kbdmap
     $ man 5 kbdmap
     $ ls -l /usr/share/syscons/keymaps | grep emacs

To make the change permanent you would modify /etc/rc.conf

     $ grep keymap /etc/defaults/rc.conf

will show you the variable you need to change.

Disclaimer: I've never done it this way.

Another method which involves changing the function of ^H in emacs but that makes it difficult to get the help system going. A short search of google for "emacs ^h backspace" will probably yield fruit. I used to do it this way and it was okay. I t really depends on how much you need the help system.

As a long time Gnu Emacs users I can say that the best way to solve this problem is to an X11 aware emacs under X-Windows. In this state emacs completely bypasses the terminal, catching and interpreting the keystroke events from the X window system. Since X can say 'The user pressed "KeyBackspace" which has an ASCII code of 0x08 (Ctrl-H)' emacs can see that as a Backspace attempt and delete the appropriate character. Further more X can differentiate that keypress from "The user pressed 'H' while holding down Ctrl which gives an ASCII code of 0x08". Emacs gets complete information from the X-Windows system and can take the right action, starting the help system.

-- Chris

      __o          "All I was doing was trying to get home from work."
    _`\<,_           -Rosa Parks
Christopher Sean Hilton                    <chris | at | vindaloo.com>
        pgp key: D0957A2D/f5 30 0a e1 55 76 9b 1f 47 0b 07 e9 75 0e 14
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