fix backspace issue in sup/debian

Create a file, /etc/inputrc for system wide use or ~/.inputrc for personal use. Actually, this is the readline initialization file, readline is a library that some programs (bash, kvt) use to read input (try bind -v to see a list of readline key and function bindings). Cut and paste the following in the file to make the Delete key delete characters under the cursor, and make Home and End work as well:

"\e[3~": delete-char
# this is actually equivalent to "\C-?": delete-char
# VT
"\e[1~": beginning-of-line
"\e[4~": end-of-line
# kvt
"\e[H":beginning-of-line
"\e[F":end-of-line
# rxvt and konsole (i.e. the KDE-app...)
"\e[7~":beginning-of-line
"\e[8~":end-of-line

If a system-wide /etc/inputrc was created, add the following line to /etc/profile:
export INPUTRC=/etc/inputrc
Make sure that the stty erase character is set to ^?. Type

stty -a | grep erase
and check if it says

erase = ^?;
If it is set to something else (e.g. ^H) then put the following line in both .bashrc and in either .bash_profile or /etc/profile:

if tty --quiet ; then
stty erase '^?'
fi

and for xterm and rxvt add this to .Xdefaults:
*ttyModes: erase ^?

If you create /etc/inputrc, note that Bash will ignore ~/.inputrc (currently this happens in all distributions except Debian, however, this might change in the future). As an alternative, you can edit ~/.inputrc, and copy this to /etc/skel/, so it's in the home directories of all new users.
Push the key-combination 'Ctrl-x-r' (push the control-key, the x-key. release it, push the r-key, release it, and then release the control-key) to see if the changes in inputrc take effect. Or just login again, and it will work.
You can also change the keybindings on the fly with the bind command, e.g:

[localhost]> bind "\C-?": backward-delete-char
This is useful to test different keybindings, if they work you can put them in ~/.inputrc. Read all about it in the readline manpage.
People using keymaps with e.g. Scandinavian characters who would like bash to display these characters (øl;-) have to add the following lines in .inputrc:
set convert-meta off
set output-meta on
set input-meta on

For more info, check the Danish-HOWTO.