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KILL(1) User Commands KILL(1)

NAME

kill - send a signal to a process

SYNOPSIS

kill [options] <pid> [...]

DESCRIPTION

The default signal for kill is TERM. Use -l or -L to list available signals. Particularly useful signals include HUP, INT, KILL, STOP, CONT, and 0. Alternate signals may be specified in three ways: -9, -SIGKILL or -KILL. Negative PID values may be used to choose whole process groups; see the PGID column in ps command output. A PID of -1 is special; it indicates all processes except the kill process itself and init.

OPTIONS

<pid> [...]
Send signal to every <pid> listed.
-<signal>
Specify the signal to be sent. The signal can be specified by using name or number. The behavior of signals is explained in signal(7) manual page.
Use sigqueue(3) rather than kill(2) and the value argument is used to specify an integer to be sent with the signal. If the receiving process has installed a handler for this signal using the SA_SIGINFO flag to sigaction(2), then it can obtain this data via the si_value field of the siginfo_t structure.
List signal names. This option has optional argument, which will convert signal number to signal name, or other way round.
List signal names in a nice table.

NOTES

Your shell (command line interpreter) may have a built-in kill command. You may need to run the command described here as /bin/kill to solve the conflict.

If you use negative PID values, you will need to specify a signal as well so that kill knows if the option is for the PID or the signal number. For example, issuing the command with the single option -9 it is not clear if you mean signal 9 (SIGKILL) or process group 9.

EXAMPLES

Kill all processes you can kill.
Translate number 11 into a signal name.
List the available signal choices in a nice table.
Send the default signal, SIGTERM, to all those processes.
Send the signal SIGTERM to process group 123. The signal name or number is required if specifying process groups with a negative PID.

SEE ALSO

kill(2), killall(1), nice(1), pkill(1), renice(1), signal(7), sigqueue(3), skill(1)

STANDARDS

This command meets appropriate standards. The -L flag is Linux-specific.

AUTHOR

Albert Cahalan wrote kill in 1999 to replace a bsdutils one that was not standards compliant. The util-linux one might also work correctly.

REPORTING BUGS

Please send bug reports to procps@freelists.org

2023-01-16 procps-ng