why we cannot kill process id 1 with command "kill -9 1"
 

why we cannot kill process id 1 with command "kill -9 1"

That's the kernel init if memory serves me correctly. Think about it, if you killed the kernel you'd crash the whole thing. So, protected.

Funny, I always thought that killing init would cause a reboot. Of course, it makes a lot of sense to protect the process that is parent to all other processes on the system.

I swear, it used to force a reboot..

Why are you trying to kill init?

Maligree/arckane
thanks for your input , It looks the init process is built in such way that it cannot be killed with "kill -9 <pid> " and that is because it shouldn't be killed as it will crash the system .

anomie
I am not trying to kill init process , its a query regarding the usage of kill command with signal 9

satyaredhat:

you can kill PID 1 init
send signal to runlevel 0 or 6

how do you send signal to runlevel?

QueenZ, you can change your current runlevel with telinit <level>. But that's definitely not what you'd call killing init.