kill(1) User Commands kill(1)
kill - terminate or signal processes
/usr/bin/kill -s signal_name pid...
/usr/bin/kill -l [exit_status]
/usr/bin/kill [-signal_name] pid...
/usr/bin/kill [-signal_number] pid...
The kill utility sends a signal to the process or processes specified
by each pid operand.
For each pid operand, the kill utility will perform actions equivalent
to the kill(2) function called with the following arguments:
1. The value of the pid operand will be used as the pid argument.
2. The sig argument is the value specified by the -s option, the -sig-
nal_name option, or the -signal_number option, or, if none of these
options is specified, by SIGTERM.
The signaled process must belong to the current user unless the user is
See NOTES for descriptions of the shell built-in versions of kill.
The following options are supported:
-l (The letter ell.) Writes all values of signal_name sup-
ported by the implementation, if no operand is given.
If an exit_status operand is given and it is a value of
the ? shell special parameter and wait corresponding to
a process that was terminated by a signal, the sig-
nal_name corresponding to the signal that terminated
the process will be written. If an exit_status operand
is given and it is the unsigned decimal integer value
of a signal number, the signal_name corresponding to
that signal will be written. Otherwise, the results are
-s signal_name Specifies the signal to send, using one of the symbolic
names defined in the <<signal.h>> description. Values of
signal_name will be recognized in a case-independent
fashion, without the SIG prefix. In addition, the sym-
bolic name 0 will be recognized, representing the sig-
nal value zero. The corresponding signal will be sent
instead of SIGTERM.
-signal_name Equivalent to -s signal_name.
-signal_number Specifies a non-negative decimal integer, signal_num-
ber, representing the signal to be used instead of
SIGTERM, as the sig argument in the effective call
The following operands are supported:
pid One of the following:
1. A decimal integer specifying a process or
process group to be signaled. The process or
processes selected by positive, negative and
zero values of the pid operand will be as
described for the kill function. If process
number 0 is specified, all processes in the
process group are signaled. If the first pid
operand is negative, it should be preceded by
-- to keep it from being interpreted as an
2. A job control job ID that identifies a back-
ground process group to be signaled. The job
control job ID notation is applicable only for
invocations of kill in the current shell execu-
Note: The job control job ID type of pid is available
only on systems supporting the job control option.
exit_status A decimal integer specifying a signal number or the
exit status of a process terminated by a signal.
Process numbers can be found by using ps(1).
The job control job ID notation is not required to work as expected
when kill is operating in its own utility execution environment. In
either of the following examples:
example% nohup kill %1 &&
example% system( "kill %1");
kill operates in a different environment and will not share the shell's
understanding of job numbers.
When the -l option is not specified, the standard output will not be
When the -l option is specified, the symbolic name of each signal will
be written in the following format:
"%s%c", <signal_name>, <separator>
where the <<signal_name>> is in upper-case, without the SIG prefix, and
the <<separator>> will be either a newline character or a space charac-
ter. For the last signal written, <<separator>> will be a newline charac-
When both the -l option and exit_status operand are specified, the sym-
bolic name of the corresponding signal will be written in the following
Example 1: Sending the kill signal
Any of the commands:
example% kill -9 100 -165
example% kill -s kill 100 -165
example% kill -s KILL 100 -165
sends the SIGKILL signal to the process whose process ID is 100 and to
all processes whose process group ID is 165, assuming the sending
process has permission to send that signal to the specified processes,
and that they exist.
Example 2: Avoiding ambiguity with an initial negative number
To avoid an ambiguity of an initial negative number argument specifying
either a signal number or a process group, the former will always be
the case. Therefore, to send the default signal to a process group (for
example, 123), an application should use a command similar to one of
example% kill -TERM -123
example% kill -- -123
See environ(5) for descriptions of the following environment variables
that affect the execution of kill: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
The following exit values are returned:
0 At least one matching process was found for each pid operand,
and the specified signal was successfully processed for at
least one matching process.
>>0 An error occurred.
See attributes(5) for descriptions of the following attributes:
tab() allbox; cw(2.750000i)| cw(2.750000i) lw(2.750000i)|
lw(2.750000i). ATTRIBUTE TYPEATTRIBUTE VALUE AvailabilitySUNWcsu
CSIenabled Interface StabilityStandard
csh(1), jobs(1), ksh(1), ps(1), sh(1), shell_builtins(1), wait(1),
kill(2), signal(3C), signal.h(3HEAD), attributes(5), environ(5), stan-
The Bourne shell, sh, has a built-in version of kill to provide the
functionality of the kill command for processes identified with a
jobid. The sh syntax is:
kill [ -sig ] [ pid ] [ %job ]...
The C-shell, csh, also has a built-in kill command, whose syntax is:
The csh kill built-in sends the TERM (terminate) signal, by default, or
the signal specified, to the specified process ID, the job indicated,
or the current job. Signals are either given by number or by name.
There is no default. Typing kill does not send a signal to the current
job. If the signal being sent is TERM (terminate) or HUP (hangup), then
the job or process is sent a CONT (continue) signal as well.
-l Lists the signal names that can be sent.
The syntax of the ksh kill is:
The ksh kill sends either the TERM (terminate) signal or the specified
signal to the specified jobs or processes. Signals are either given by
number or by names (as given in signal.h(3HEAD) stripped of the SIG
prefix). If the signal being sent is TERM (terminate) or HUP (hangup),
then the job or process will be sent a CONT (continue) signal if it is
stopped. The argument job can be the process id of a process that is
not a member of one of the active jobs. In the second form, kill -l,
the signal numbers and names are listed.
SunOS 5.10 2 Oct 2001 kill(1)