In a standard Linux system, processes talk via Unix Sockets or Pipes. But in Android, almost everything happens through the Binder IPC (Inter-Process Communication) mechanism. This is the nervous system of your smartphone.
The Binder is a custom kernel driver that allows high-performance communication between processes. When you use termux-battery-status, Termux isn't talking to the hardware directly; it is sending a "Binder Transaction" to the Android System Server.
As a System Architect, you can peek into how your environment is interacting with the Android framework by using the service command.