Re: recognizing an xterm running only bash from the CLI

[Nicolas George <george@nsup.org>]

Mike McClain (HE12025-08-11):
> I've defined to9 () { echo "$1" > /dev/tty9 } to be used from an xterm.
> I'd like to have a similar function toX() to be used on a virtual
> terminal that would print some text on the xterm running only bash
> but that xterm varies which /dev/pts/? it's running on and so far
> I've not found a way without manually going into X and entering 'tty'
> on that xterm to find out which /dev/pts to direct an echo to.
> If I can learn how to determine which /dev/pts/? is running only bash
> and not mc or something else then I can write toX() to just work.

So this was a XY problem.

Do not try to guess which terminal is running “only bash”, have the
terminal you want run something before bash or when bash starts to
prepare what you want.

Before bash: xterm -e 'something ; $SHELL'

When bash starts: vim .bashrc

As for the best way to prepare what you want…

You first need to determine the tty of the script. With zsh it would be
easy, that is $TTY; bash does not have that convenient feature, so you
will need TTY=$(tty).

Then you need to export that information. There are many ways. An old
convention that group-writable ttys are for receiving message. So:
“chmod g+w $TTY”. Or you can use a symlink at a specific place:
“ln -s $TTY $XDG_RUNTIME_DIR/my_message_tty”. There are other
possibilities.

Regards,

-- 
  Nicolas George