I'm battling with a similar problem:
getting text by key presses into other process.
AFAIR it can be done by using: fg, bg, <pid>.
Years ago I managed to select for playing, any 1 of N *.wav,
having only an on/of-power-switch to my battery-operated RPi.
Now I can't even understand [nor find documentation] how multiple
PIDs can give extra <control>.
Where to find ?