[BRLTTY] Key combinations not (yet?) handled by the Linux virtual console

[Nicolas Pitre]

On Mon, 24 Nov 2025, Sébastien Hinderer wrote:

> Dear all,
> 
> I assume the question is more for Nicolas but I am posting here as it
> may be of general interest.
> 
> It seems the virtual consoles do not (yet?) have the capacity to
> distinguish e.g. Enter from Contro-Enter,

It does. Try this:

$ cat > ~/ctrl-enter.map << EOF
control keycode 28 = F100
string F100 = "foobar"
EOF

$ sudo loadkeys ~/ctrl-enter.map

> combine shift with tabl,

Shift+Tab is typically already mapped to Meta_Tab "\033\t".

> control or the arrow keys.

Same deal. 

> I am wondering whether such limitations are intrinsic to the console and
> thus impossible to overcome for some reason, or whether it's just
> that the support for such key combinations has not been implemented
> yet and could be added?

You can add mappings to the following combinations for any key:

- plain
- shift
- control
- alt
- shift+control
- shift+alt
- control+alt
- shift+control+alt

To see what's already mapped, do:

$ dumpkeys --full-table | less -S
(with less -S you may pan left and right)

You'll notice that the vast majority is unmapped.


Nicolas