KILL(1) User Commands KILL(1)NAME
kill - terminate a process
kill [-s signal|-p] [-q sigval] [-a] [--] pid...
kill -l [signal]
The command kill sends the specified signal to the specified process or
process group. If no signal is specified, the TERM signal is sent.
The TERM signal will kill processes which do not catch this signal.
For other processes, it may be necessary to use the KILL (9) signal,
since this signal cannot be caught.
Most modern shells have a builtin kill function, with a usage rather
similar to that of the command described here. The '-a' and '-p'
options, and the possibility to specify processes by command name are a
If sig is 0, then no signal is sent, but error checking is still per‐
pid... Specify the list of processes that kill should signal. Each pid
can be one of five things:
n where n is larger than 0. The process with pid n will be
0 All processes in the current process group are signaled.
-1 All processes with pid larger than 1 will be signaled.
-n where n is larger than 1. All processes in process group
n are signaled. When an argument of the form '-n' is
given, and it is meant to denote a process group, either
the signal must be specified first, or the argument must
be preceded by a '--' option, otherwise it will be taken
as the signal to send.
All processes invoked using that name will be signaled.
-s, --signal signal
Specify the signal to send. The signal may be given as a signal
name or number.
-l, --list [signal]
Print a list of signal names, or convert signal given as argu‐
ment to a name. The signals are found in /usr/include/linux/
Similar to -l, but will print signal names and their correspond‐
Do not restrict the commandname-to-pid conversion to processes
with the same uid as the present process.
Specify that kill should only print the process id (pid) of the
named processes, and not send any signals.
-q, --queue sigval
Use sigqueue(2) rather than kill(2) and the sigval 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.
It is not possible to send a signal to explicitly selected thread in a
multithreaded process by kill(2) syscall. If kill(2) is used to send a
signal to a thread group, then kernel selects arbitrary member of the
thread group that has not blocked the signal. For more details see
clone(2) CLONE_THREAD description.
The command kill(1) as well as syscall kill(2) accepts TID (thread ID,
see gettid(2)) as argument. In this case the kill behavior is not
changed and the signal is also delivered to the thread group rather
than to the specified thread.
SEE ALSObash(1), tcsh(1), kill(2), sigvec(2), signal(7)AUTHOR
Taken from BSD 4.4. The ability to translate process names to process
ids was added by Salvatore Valente ⟨email@example.com⟩.
The kill command is part of the util-linux package and is available
from Linux Kernel Archive ⟨ftp://ftp.kernel.org/pub/linux/utils/util-
util-linux March 2013 KILL(1)