Earlier quoted context omitted.
I solved that problem some time ago with netcat, „coproc nc -l -p PORT“. Makes bash listen to nc‘s stdout and let’s it write to it‘s stdin. But nc is not bash.
Here's my nc version, works on all shells: https://gist.github.com/alganet/140c7c12d1603c244a01 nc is almost everywhere, you can count on it. Ultimately, this is a toy, but it can be handy. I originally made it to attempt using for serving config for networked debian unattended installations[1] while automating VM creation, but never went that far. [1]: https://debian-handbook.info/browse/en-US/stable/sect.automa...
That's a problematic distinction in some situations.