init Command - Process Control Initialization

The init command is the parent of all processes and is responsible for system initialization and runlevel changes on traditional UNIX and Linux systems. On modern systems, it is often replaced by systemd and managed via systemctl.

Syntax

init [runlevel]

Examples

init 0

init 6

init 3

Notes

• init is the first process started by the kernel and has PID 1.
• On systemd-based systems, use systemctl to manage system state and targets.
• Changing runlevels may disrupt users and services.