Kill Command in Linux: How to End Processes with SIGTERM and SIGKILL

The kill command in Linux sends signals to processes.

It is generally used to terminate the execution of processes identified by their PID.

If no specific signal is passed as a parameter, kill will send the SIGTERM (15) signal to terminate the process gracefully.

In this example, kill forces the web server identified by PID 1953 to re-read its configuration file:

$ ps aux | grep httpdwwwrun 1952 0.0 1.7 93232 2248 ?	S	16:15	0:00 /usr/sbin/httpd -f /etc/httpd/httpd.confwwwrun 1953 0.0 1.7 93232 2248 ?	S	16:15	0:00 /usr/sbin/httpd -f /etc/httpd/httpd.confwwwrun 1954 0.0 1.7 93232 2248 ?	S	16:15	0:00 /usr/sbin/httpd -f /etc/httpd/httpd.conf

# kill –HUP 1953

Abruptly terminates the web service processes with PIDs 1953 and 1954:

# kill –9 1953 1954

The -l option of kill provides a list of signals and their respective codes:

$ kill -l
 1) SIGHUP    2) SIGINT   3) SIGQUIT  4) SIGILL   5) SIGTRAP
 6) SIGABRT   7) SIGBUS   8) SIGFPE   9) SIGKILL 10) SIGUSR1
11) SIGSEGV  12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM
( ... )

A command that makes it easier to send signals to processes that have multiple child processes is killall.

Learn much more about Linux in our online course. You can enroll here. If you already have an account, or want to create one, just log in or create your user here.

Liked it? Share