telinit

Telinit is a command line tool in Linux used to change the runlevel or system initialization mode. Runlevels determine the services and processes running on a Linux system during different stages of booting. The telinit command is typically used to change the runlevel of a Linux system manually.

It is primarily used by system administrators to perform various tasks related to system maintenance or troubleshooting. Telinit can be executed with various runlevel arguments to initiate different modes, such as single-user mode, multi-user mode, or rebooting the system.

To use telinit, root privileges are generally required as it manipulates critical system processes. It is particularly useful if there is a need to change the system's state without rebooting.

The telinit command can be executed with arguments like 0, 1, 2, 3, 4, 5, 6, or S (or s) representing different runlevels or states. Each runlevel corresponds to a different set of services and scripts that will be executed when the system enters that particular runlevel.

Overall, telinit is a powerful command line tool in Linux that allows system administrators to change the runlevel and control various aspects of system initialization and maintenance.