init, telinit — Process Control Initialization
/sbin/init [0123456abcQqSs] /etc/telinit [0123456abcQqSs]
The init command is a general process-spawner. init is the parent of all other processes. init examines the contents of the /etc/inittab file to determine the order for starting up other processes and what to do when one of those processes ends. Use telinit, which is linked to /sbin/init, to direct the actions of init. telinit takes a one-character argument and signals init to take the appropriate action.
init and telinit can be run only by a privileged user.
Do not use the S or s (single user) state indiscriminately in /etc/inittab. When modifying this file, it is best to avoid adding the s or S state to any line ...