Kill Command

UNIX for Beginners Q & A UNIX for Dummies Questions & Answers
1

Hi All,
What is difference between kill & kill -9 command?

Thanks & regards,
Sonali

2

type man kill

3

Kill is used for graceful killing where as kill -9 is unconditional. That means,
when you use -9 the program will will shut by bruteforce.

4

'kill' sends a SIGTERM signal to the process so it can exit cleanly(close file ptr, flush buffers, etc, and exit), 'kill -9' asks the OS to close the process. That's the only signal that is not delivered to the process,. so it can not handle.

5

if it is not delivered the process, how is the kernel able to terminate the process forcefully?

It is delivered.

signal handlers for -9 cannot be registered.

Along with -9 there is one more
SIGSTOP which stops the process and cannot be handled.