init stands for initialization. In simple words the role of init is to create processes from script stored in the file /etc/inittab which is a configuration file which is to be used by initialization system. It is the last step of the kernel boot sequence.
What is the primary role of init?
The init command initializes and controls processes. Its primary role is to start processes based on records read from the /etc/inittab file. … The init command controls autonomous processes required by the system.
What does init 1 do in Linux?
Basically in Linux every runlevel is associated with certain programs or programs are associated with various runlevels. So entering that level with init 1 will kill all programs that are not designed or meant to be in that runlevel, hence the computer freeze mentioned by you.
What does init 0 do in Linux?
Basically init 0 change the current run level to run level 0. shutdown -h can run by any user but init 0 can only run by superuser. Essentially the end result is the same but shutdown allows useful options which on a multiuser system creates less enemies 
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What happens if init is killed?
Init is the first process in linux. Logically it is the parent process of all the processes. Yes you can kill the init process by kill -9 . Once you kill the init process rest processes will become zombie process and system will stop functioning.
What is the difference between init 6 and reboot?
In Linux, the init 6 command gracefully reboots the system running all the K* shutdown scripts first, before rebooting. The reboot command does a very quick reboot. It doesn’t execute any kill scripts, but just unmounts filesystems and restarts the system. The reboot command is more forceful.
How do I shut down Linux?
Alternatively you can press the key combination Ctrl+Alt+Del . A last option is to log in as root and type one of the commands poweroff, halt or shutdown -h now if either of the key combinations do not work or you prefer to type commands; use reboot to reboot the system.
What is the use of init 6 in Linux?
The init 6 command stops the operating system and reboots to the state that is defined by the initdefault entry in the /etc/inittab file.
What is run level in Linux?
A runlevel is an operating state on a Unix and Unix-based operating system that is preset on the Linux-based system. Runlevels are numbered from zero to six. Runlevels determine which programs can execute after the OS boots up.
What is run level 4 in Linux?
A runlevel is a mode of operation in the computer operating systems that implements Unix System V-style initialization. … For example, runlevel 4 might be a multi-user GUI no-server configuration on one distribution, and nothing on another.
What is halt command in Linux?
This command in Linux is used to instruct the hardware to stop all the CPU functions. Basically, it reboots or stops the system. If the system is in runlevel 0 or 6 or using the command with –force option, it results in rebooting of the system otherwise it results in shutdown. Syntax: halt [OPTION]…
What is Sudo init5?
init 5 is a runlevel . A runlevel basically initializes the system by starting software. Runlevel 5 is usually used to start in graphical mode. If you start in a non-graphical mode, or you open a tty (in general Ctrl-F1 through Ctrl-F6 ) startx can start X in another tty (F7 – F9).