Can you explain what the 'init' command in an operating system means and how it functions?

The init command in an operating system is the first process that starts after the kernel loads. It is responsible for system initialization: launching services, configuring the environment, and preparing the system for user operation.

In traditional Unix-like systems, init has PID 1 and manages the lifecycle of all other processes. It reads configuration files (for example, /etc/inittab), launches daemons, and sets runlevels.

In modern systems, init can be replaced with more advanced initialization systems, such as systemd, but the essence remains the same — managing the start and stop of services and processes during system boot and shutdown.