How can I run a startup script for GNURoot Debian? I've installed GNURoot debian on a rooted Android device and I can launch a debian shell programmatically using am, but I couldn't figure out how to run a command like starting dropbear.

What's the recommended way of running a command straight after launching and GNURoot Debian shell ?
To install:
apt install dropbear  

To start:
service start dropbear

Autostart:
Make sure enable is set to 1 in /etc/config/dropbear.