kill Command: Tutorial & Examples
Send a signal to a process
The kill
command is a utility in Linux that allows you to send a signal to a process, causing it to terminate or perform some other action. The signal can be specified using a
signal name or signal number.
Here is the basic syntax for using kill:
kill [-s signal] pid
The pid
argument is the process ID of the process that you want to send a signal to.
Here are some common signals that can be used with kill:
SIGHUP
(1
): This signal is typically used to hang up or terminate a process that is running in the background.SIGINT
(2
): This signal is sent when the user pressesCTRL+C
on the keyboard. It is typically used to interrupt a process.SIGKILL
(9
): This signal cannot be caught or ignored, and it immediately terminates the process.SIGTERM
(15
): This signal requests that the process terminate gracefully. The process can choose to catch or ignore this signal.SIGCONT
(18
): This signal continues a stopped process.SIGSTOP
(19
): This signal stops the process and cannot be caught or ignored.
To send the SIGKILL
signal to a process with a process ID of 123
:
kill -9 123
It's worth noting that only processes that the user has permission to signal can be signaled using kill
. Also, some processes may have special behavior when signaled, such as
ignoring certain signals or performing some other action in response to the signal.