how to backspace in vi 2557

Unfortuneately not. Various programs have various demands as to what character will act as a backspace. Some programs have ^H hard wired in. If they do not see a ^H they will not erase the character behind the cursor. Others like emacs use ^H for other purppses and demand that you use ^?. some like the tty are programable (eg with stty) as to what they will accept as the backspace code. Thus it is impossible to set up your keyboard so that all programs will use the backspace key as "erase the character in front of the cursor and move the cursor one space to the left". The problem is precisely that it is not a simply matter.

I guess it could be worse and EBCDIC could be in compebreastion with ASCII -- ie the IBM keyboard could have dominated rather than the VT Dec keyboard, in compebreastion with the PC ASCII based keyboard. Otherwise half your programs would have used an entirely different encoding even for the letters from the other half.

I really really wish that people had taken the ASCII standad seriously and used ^H as the backspace key. But ^? seems to have won out, much to the confusion of all.