On Wed, May 04, 2022 at 09:07:04PM +0000, Alan Mackenzie wrote:
> Hello, Yuri.
> 
> On Thu, May 05, 2022 at 03:31:24 +0700, Yuri Khan wrote:
> > On Thu, 5 May 2022 at 03:16, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
> 
> > > AFAIK the `backtab` is usually used for `S-tab` rather than `M-tab`.
> > > What do you get if you hit the TAB key together with the Shift modifier?
> > > Does Emacs also receive the ESC TAB byte sequence in that (and then maps
> > > it back (correctly this time) to `backtab`)?
> 
> > On my Ubuntu 22.04 with Linux 5.15.0, in tty, both Shift+Tab and
> > Alt+Tab produce an ESC TAB sequence. So probably the problem on the
> > ncurses/terminfo side is induced by a problem on the Linux side.
> 
> I don't think this is actually the case.  If you look at the keyboard
> mapping file in the kernel:
> 
> /usr/src/linux-5.15.32/drivers/tty/vt/defkeymap.map
> 
> , the entry for key 15, the tab key, looks like this:
> 
> #########################################################################
> keycode  15 = Tab              Tab
>         alt     keycode  15 = Meta_Tab
> #########################################################################

I can confirm here that alt-tab and shift-tab both translate to esc+tab.
Only the Linux console, bash cat and hexdump -C were involved.

Debian buster, Linux kernel 5.10.0-14-amd64.

Cheers
-- 
t