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KILL

Section: User Commands (1)
Updated: 202-1-27
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NAME

kill - send a signal to one or more processes

SYNOPSIS

kill [-q~value|--queue~value] pid ... kill -signal [-q~value|--queue~value] pi-o-pgid ...
kill -s~signal [-q~value|--queue~value] pi-o-pgid ...
kill --signal~signal [-q~value|--queue~value] pi-o-pgid ... kill -l~[signal]
kill --list~[signal] kill -L
kill --table

DESCRIPTION

kill sends a signal to one or more processes by pid or pgid, a process or process group identifier. signal(7) explains the varieties and behavior of signals. kill's default signal is TERM. The -l and -L options list available signals. Particularly useful signals include HUP, INT, KILL, STOP, CONT, and 0. Specify signals by number, by name, or by name with a [lq]SIG[rq] prefix; for example, -9, -SIGKILL, and -KILL are equivalent. A negative operand selects a process group; see the PGID column in ps(1) command output. A pid of -1 is special; it indicates all processes except the kill process itself and init(8). The -q option uses an alternative signaling method to to additionally transmit an integral value to a receiving process. If that process has installed a handler for the signal and specified the SA_SIGINFO flag to sigaction(2), then it can obtain this datum via the si_value field of the siginfo_t structure.

OPTIONS

-signal: -s~signal --signal~signal Send signal by name or number as described above. If signal is 0 (zero), kill sends no signal, but still validates its operands; this behavior permits the caller to check whether the specified pids and/or pgids exist and it has permission to send them signals.
-q~value: --queue~value Use sigqueue(3) rather than kill(2) to additionally send value to each pid or pgid.
-l~[signal]: --list~[fIsignal] Without an argument, list signal names. The optional argument causes kill to convert the specified signal from name to numeric form, or vice versa as appropriate, and report the translation.
-L: --table List signal names in tabular format.

NOTES

The shell (comman-line interpreter) often has a buil-in [lq]kill[rq] command. You may need to run the command described here as /bin/:kill to override the shell buil-in.

If you use a negative operand, specify a signal by name or number first so that kill can distinguish it from a process group. For example, the command [lq]kill 123 -9[rq] is ambiguous; it could mean to kill process 123 with signal 9, or to kill process 123 and process group 9 with the default signal.

EXAMPLES

kill -HUP -1: Send hangup signal to all the processes you can.
kill -l 11: Report name corresponding to signal number 11.
kill 123 543: Send the default signal, SIGTERM, to processes 123 and 543.
kill-SIGTERM-123: Send the signal SIGTERM to process group 123.

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