kill(1)kill(1)NAMEkill - Sends a signal to a running process
SYNOPSISkill-l [exit_status]
kill [-signal_name | signal_number] process_ID...
kill-s signal_name process_ID...
Note
The C shell has a built-in version of the kill command. If you are
using the C shell, and want to guarantee that you are using the command
described here, you must specify the full path /usr/bin/kill. See the
csh(1) reference page for a description of the built-in command.
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
kill: XCU5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
OPTIONS
The kill command supports the following options: Lists signal names.
If you specify an exit status (a numeric value) or the shell
special parameter $?, which expands to the exit status of the
most recent pipeline, kill prints the name of the terminating
signal. Specifies the signal to send, using one of the symbolic
names defined for required signals or job control signals. Val‐
ues of signal_name are recognized in both uppercase or lowercase
letters, and without the SIG prefix. The symbolic name 0
(zero), which represents the value 0 (zero), is also recognized.
The corresponding signal is sent instead of SIGTERM. Specifies
the signal to send to the process. You can specify either a
name, stripped of the SIG prefix (such as KILL), or a number
(such as 9). For information about signal names and numbers,
see the sigaction() system call.
OPERANDS
A process identification number
[Tru64 UNIX] There are several special process identification
numbers (PIDs) that you can specify to cause the following spe‐
cial actions: The signal is sent to all processes having a
process group ID equal to the process group ID of the sender,
except those with a process ID of 0 (zero) and the process ID of
the init process.
Signals using this PID do not span cluster members. If the
effective user ID of the sender is not 0 (root), the signal is
sent to all processes with a process group ID equal to the
effective user ID of the sender, except those with a process ID
of 0 (zero) and the process ID of the init process.
If the effective user ID of the sender is 0 (root), the signal
is sent to all processes (on the current member if a cluster),
except the process ID of 0 (zero) and the process ID of the init
process.
Signals using this PID do not span cluster members. The signal
is sent to all processes whose process group number is equal to
the absolute value of PID. This is true even in the case of a
cluster where the process to receive the signal is on another
cluster member. Note that when you specify any negative PID,
you must also specify the signal to be sent, even the default
signal SIGTERM. A decimal integer specifying a signal number or
the exit status of a process terminated by a signal.
DESCRIPTION
The kill command sends a signal to one or more running processes. The
default is the SIGTERM signal (signal number 15), which usually termi‐
nates processes that do not ignore or catch the signal.
You identify the process to be signaled by specifying its process iden‐
tification number (also known as the process ID or PID). The shell dis‐
plays the PID of each process that is running in the background or, if
you start more than one process in a pipeline, the shell displays the
number of the last process. You can also use the ps command to display
PIDs.
[Tru64 UNIX] The name of the kill command is misleading because many
signals, including SIGUSR1, do not terminate processes.
[Tru64 UNIX] Unless you are operating with superuser privileges, the
process you want to signal must belong to you. When operating with
superuser authority, you can signal any process.
[Tru64 UNIX] See the kill() system call for a complete discussion of
kill. Note that the csh command contains a built-in subcommand named
kill, but the command and subcommand do not necessarily work in the
same way. For information on the subcommand, see csh.
[Tru64 UNIX] In a TruCluster Server cluster, if the passed parameter
is greater than zero (0), the signal is sent to the process whose PID
matches the passed parameter, no matter on which cluster member it is
running. If the passed parameter is less than -1, the signal is sent
to all processes (cluster-wide) whose process group ID matches the
absolute value of the passed parameter.
NOTES
Some applications and scripts depend on the process ID of the init pro‐
gram being 1 (one): do not depend on it. Instead, use standard meth‐
ods, such as the ps and grep commands, to obtain all process IDs.
EXIT STATUS
The following exit values are returned: At least one matching process
was found, and the specified signal was successfully processed for at
least one matching process. An error occurred.
EXAMPLES
The following command terminates the process with the specified PID:
kill 1095
This command terminates process 1095 by sending it the default
SIGTERM signal. Note that process 1095 might not actually ter‐
minate if it has made special arrangements to ignore or catch
the SIGTERM signal. The following command terminates several
processes that ignore the default signal: kill-KILL 17285 15692
This command sends SIGKILL to processes 17285 and 15692. The
SIGKILL signal usually cannot be ignored or caught. The follow‐
ing command terminates all of your background processes. Signals
using this PID do not span cluster members. kill 0
This command sends the SIGTERM signal to all members of the
shell process group. This includes all background processes
started with &. Although the signal is sent to the shell, it has
no effect because the shell ignores the default signal 15. The
following command terminates all of your processes and logs you
out. Signals using this PID do not span cluster members. kill-KILL 0
This command sends SIGKILL to all members of the shell process
group. Because the shell cannot ignore SIGKILL, this also ter‐
minates the login shell and logs you out. If you are using mul‐
tiple windows, this closes the active window. The following
command terminate all the processes that you own. Signals using
this PID do not span cluster members. kill-KILL -1
This command sends SIGKILL to all the processes that you own,
even those that belong to other process groups. If you are
using multiple windows, this command closes all the windows.
The following command sends a specific signal to a specific
process: kill-USR1 1103
This command sends the SIGUSR1 signal to process 1103. The
action taken on the SIGUSR1 signal is defined by the particular
application you are running. The following command lists the
signal names in numerical order, stripped of the SIG prefix:
kill-l
1) HUP 13) PIPE 25) XFSZ 37)
RTMIN+4
2) INT 14) ALRM 26) VTALRM 38)
RTMIN+5
3) QUIT 15) TERM 27) PROF 39)
RTMIN+6
4) ILL 16) URG 28) WINCH 40)
RTMIN+7
5) TRAP 17) STOP 29) PWR 41)
RTMAX-7
6) LOST 18) TSTP 30) USR1 42)
RTMAX-6
7) EMT 19) CONT 31) USR2 43)
RTMAX-5
8) FPE 20) CHLD 32) RESV 44)
RTMAX-4
9) KILL 21) TTIN 33) RTMIN 45)
RTMAX-3 10) BUS 22) TTOU 34) RTMIN+1
46) RTMAX-2 11) SEGV 23) POLL 35) RTMIN+2
47) RTMAX-1 12) SYS 24) XCPU 36) RTMIN+3
48) RTMAX
The command output can vary from system to system.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of kill: Pro‐
vides a default value for the internationalization variables that are
unset or null. If LANG is unset or null, the corresponding value from
the default locale is used. If any of the internationalization vari‐
ables contain an invalid setting, the utility behaves as if none of the
variables had been defined. If set to a non-empty string value, over‐
rides the values of all the other internationalization variables.
Determines the locale for the interpretation of sequences of bytes of
text data as characters (for example, single-byte as opposed to multi‐
byte characters in arguments). Determines the locale for the format
and contents of diagnostic messages written to standard error. Deter‐
mines the location of message catalogues for the processing of LC_MES‐
SAGES.
FILES
Specifies signal names.
SEE ALSO
Commands: csh(1), killall(8), ksh(1), ps(1), Bourne shell sh(1b),
POSIX shell sh(1p)
Functions: kill(2), sigaction(2)
Standards: standards(5)kill(1)
