Backspace at login doesnt work despite of ttyconf

[Kavitha_K]

Hi,

On a 11.31 ia64; I am seeing this same issue of backspace causing garbled login credentials.
I used following to get backspace to work even at login, as suggested in some previous threads;
stty erase "^H" kill "^U" < /dev/ttyconf

But, doesn't ^H translate to shift+backspace ?

So, on the same lines, I tried doing;
stty erase "^?" kill "^U" < /dev/ttyconf

It succeeded in setting;
stty < /dev/ttyconf
erase = DEL; kill = ^U;
swtch ;

But, this doesn't resolve the issue of garbled input at login if I use backspace now!

If its of any help, my TERM type is xterm.
Any clue?

[Hein van den Heuvel]

>> suggested in some previous threads;

Which one? This one seemed best...

http://forums13.itrc.hp.com/service/forums/questionanswer.do?threadId=1384334

( found back with google:+backspace +login +site:itrc.hp.com )


>> But, doesn't ^H translate to shift+backspace ?

The control key brings all characters into the 'low range', below a 'space' = 32 = 0x20 in value.
It clears the top 3 bits in a character.
You could see that as subtracting 32.

There is no additional modification for uppercase/lowercase.

There couldn't be, because then the value would would come back into the normal character code range.
"A" = 65
Minus 32 that would be 33 = "!"


Is that part clear?
Regards,
Hein.

[Steven Schweda]

> If its of any help, my TERM type is xterm.

But what is your actual terminal (or
emulator), and what does it send when you hit
your backspace key? If you try Ctrl/H
instead of using your backspace key, that
last question should matter less.

[Kavitha_K]

Hein,

http://forums13.itrc.hp.com/service/forums/questionanswer.do?threadId=1384334

( found back with google:+backspace +login +site:itrc.hp.com )
-- Yes. I referred to this thread as well.

>> But, doesn't ^H translate to shift+backspace ?

The control key brings ....33 = "!"
Is that part clear?

-- I agree to this explanation. Thank you. My query was that with erase=^H ; I need to use the keys ctrl+H on the keyboard for erasing.
But if I would want to use the 'backspace key' for erasing, I do the setting with ;

stty erase "^?" kill "^U" < /dev/ttyconf (as I said above).

It doesn't work i.e. login doesn't happen successfully. Any idea why so? Could there be a restriction on what values 'erase' can have?

[Tingli]

What kind terminal emulation you use to connect to system?

[Laurent Menase · Accepted solution]

you should check the del char with "xd -xc"
and "stty -a to check that intr is not also mapped to the same char as erase.

[Aneesh Mohan]

Hi Kavitha,

Try this.

stty kill '^X' intr '^C' werase '^W'

Aneesh

[Kavitha_K]

Hi,
I checked, the current terminal settings. It was;
stty -a < /dev/ttyconf
min = 4; time = 0;
intr = DEL; quit = ^\; erase = DEL; kill = @
eof = ^D; eol = ^@; eol2 ; swtch
stop = ^S; start = ^Q; susp ; dsusp
werase ; lnext

As advised, I verified, the intr and erase were the same characters. So I did this;
stty kill '^X' intr '^C' werase '^W' erase '^?' stty -a < /dev/ttyconf
min = 4; time = 0;
intr = ^C; quit = ^\; erase = DEL; kill = ^X
eof = ^D; eol = ^@; eol2 ; swtch
stop = ^S; start = ^Q; susp ; dsusp
werase = ^W; lnext

and it WORKS now! Thank you so much everyone for your assistance.

[Bill Hassell]

> stty erase "^H" kill "^U" < /dev/ttyconf
> But, doesn't ^H translate to shift+backspace ?

No, the stty interpretation for "^H" is control-H which on standard ASCII keyboards is the backspace key.

> So, on the same lines, I tried doing;
stty erase "^?" kill "^U" < /dev/ttyconf

And control-? is the delete key (hence the word DEL in stty output).

> It succeeded in setting;
> stty < /dev/ttyconf
> erase = DEL; kill = ^U;

I'm not sure why you want to use the DEL key for a backspace -- that is more common for DEC environments. Have you mapped the Xwindow backspace key to the DEL key?

[Dennis Handly]

>Bill: I'm not sure why you want to use the DEL key for a backspace - that is more common for DEC environments. Have you mapped the Xwindow backspace key to the DEL key?

I think windows uses DEL? I have problems using keyboards configured by other users.

Also some emulators allow you to configure whether backspace does a control-H or DEL.