Originální popis anglicky:
kill - terminate or signal processes
Návod, kniha: POSIX Programmer's Manual
kill -s signal_name pid ...
kill -l
[exit_status]
kill [-signal_name] pid ...
kill
[-signal_number]
pid ...
The
kill utility shall send a signal to the process or processes
specified by each
pid operand.
For each
pid operand, the
kill utility shall perform actions
equivalent to the
kill() function defined in the System Interfaces
volume of IEEE Std 1003.1-2001 called with the following
arguments:
- *
- The value of the pid operand shall be used as the
pid argument.
- *
- The sig argument is the value specified by the
-s option, - signal_number option, or the -
signal_name option, or by SIGTERM, if none of these options is
specified.
The
kill utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines,
except that in the last two SYNOPSIS forms, the
-
signal_number and
- signal_name options are usually more
than a single character.
The following options shall be supported:
- -l
- (The letter ell.) Write all values of signal_name
supported 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 (see Special Parameters and wait() )
corresponding to a process that was terminated by a signal, the
signal_name corresponding to the signal that terminated the process
shall be written. If an exit_status operand is given and it is the
unsigned decimal integer value of a signal number, the signal_name
(the symbolic constant name without the SIG prefix defined in the
Base Definitions volume of IEEE Std 1003.1-2001)
corresponding to that signal shall be written. Otherwise, the results are
unspecified.
- -s signal_name
-
Specify the signal to send, using one of the symbolic names defined in the
<signal.h> header. Values of signal_name shall be
recognized in a case-independent fashion, without the SIG prefix.
In addition, the symbolic name 0 shall be recognized, representing the
signal value zero. The corresponding signal shall be sent instead of
SIGTERM.
- -signal_name
-
Equivalent to -s signal_name.
- -signal_number
-
Specify a non-negative decimal integer, signal_number, representing
the signal to be used instead of SIGTERM, as the sig argument in
the effective call to kill(). The correspondence between integer
values and the sig value used is shown in the following table.
The effects of specifying any
signal_number other than those listed in
the table are undefined.
| signal_number |
sig Value |
| 0 |
0 |
| 1 |
SIGHUP |
| 2 |
SIGINT |
| 3 |
SIGQUIT |
| 6 |
SIGABRT |
| 9 |
SIGKILL |
| 14 |
SIGALRM |
| 15 |
SIGTERM |
If the first argument is a negative integer, it shall be interpreted as a
- signal_number option, not as a negative
pid operand
specifying a process group.
The following operands shall be 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 shall be as described for the
kill() function. If process number 0 is specified, all processes in
the current process group shall be signaled. For the effects of negative
pid numbers, see the kill() function defined in the System
Interfaces volume of IEEE Std 1003.1-2001. If the first
pid operand is negative, it should be preceded by
"--" to keep it from being interpreted as an option.
- 2.
- A job control job ID (see the Base Definitions volume of
IEEE Std 1003.1-2001, Section 3.203, Job Control Job ID)
that identifies a background process group to be signaled. The job control
job ID notation is applicable only for invocations of kill in the
current shell execution environment; see Shell Execution
Environment .
- exit_status
- A decimal integer specifying a signal number or the exit
status of a process terminated by a signal.
Not used.
None.
The following environment variables shall affect the execution of
kill:
- LANG
- Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization
Variables for the precedence of internationalization variables used to
determine the values of locale categories.)
- LC_ALL
- If set to a non-empty string value, override the values of
all the other internationalization variables.
- LC_CTYPE
- Determine 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).
- LC_MESSAGES
- Determine the locale that should be used to affect the
format and contents of diagnostic messages written to standard error.
- NLSPATH
- Determine the location of message catalogs for the
processing of LC_MESSAGES .
Default.
When the
-l option is not specified, the standard output shall not be
used.
When the
-l option is specified, the symbolic name of each signal shall
be written in the following format:
"%s%c", <signal_name>, <separator>
where the <
signal_name> is in uppercase, without the
SIG
prefix, and the <
separator> shall be either a <newline> or
a <space>. For the last signal written, <
separator> shall
be a <newline>.
When both the
-l option and
exit_status operand are specified, the
symbolic name of the corresponding signal shall be written in the following
format:
The standard error shall be used only for diagnostic messages.
None.
None.
The following exit values shall be 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.
Default.
The following sections are informative.
Process numbers can be found by using
ps.
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:
nohup kill %1 &
system("kill %1");
the
kill operates in a different environment and does not share the
shell's understanding of job numbers.
Any of the commands:
kill -9 100 -165
kill -s kill 100 -165
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.
The System Interfaces volume of IEEE Std 1003.1-2001 and this
volume of IEEE Std 1003.1-2001 do not require specific signal
numbers for any
signal_names. Even the
- signal_number
option provides symbolic (although numeric) names for signals. If a process is
terminated by a signal, its exit status indicates the signal that killed it,
but the exact values are not specified. The
kill -l option,
however, can be used to map decimal signal numbers and exit status values into
the name of a signal. The following example reports the status of a terminated
job:
job
stat=$?
if [ $stat -eq 0 ]
then
echo job completed successfully.
elif [ $stat -gt 128 ]
then
echo job terminated by signal SIG$(kill -l $stat).
else
echo job terminated with error code $stat.
fi
To send the default signal to a process group (say 123), an application should
use a command similar to one of the following:
kill -TERM -123
kill -- -123
The
-l option originated from the C shell, and is also implemented in the
KornShell. The C shell output can consist of multiple output lines because the
signal names do not always fit on a single line on some terminal screens. The
KornShell output also included the implementation-defined signal numbers and
was considered by the standard developers to be too difficult for scripts to
parse conveniently. The specified output format is intended not only to
accommodate the historical C shell output, but also to permit an entirely
vertical or entirely horizontal listing on systems for which this is
appropriate.
An early proposal invented the name SIGNULL as a
signal_name for signal 0
(used by the System Interfaces volume of IEEE Std 1003.1-2001 to
test for the existence of a process without sending it a signal). Since the
signal_name 0 can be used in this case unambiguously, SIGNULL has been
removed.
An early proposal also required symbolic
signal_names to be recognized
with or without the
SIG prefix. Historical versions of
kill have
not written the
SIG prefix for the
-l option and have not
recognized the
SIG prefix on
signal_names. Since neither
applications portability nor ease-of-use would be improved by requiring this
extension, it is no longer required.
To avoid an ambiguity of an initial negative number argument specifying either a
signal number or a process group, IEEE Std 1003.1-2001 mandates
that it is always considered the former by implementations that support the
XSI option. It also requires that conforming applications always use the
"--" options terminator argument when specifying a process
group, unless an option is also specified.
The
-s option was added in response to international interest in
providing some form of
kill that meets the Utility Syntax Guidelines.
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:
nohup kill %1 &
system("kill %1");
the
kill operates in a different environment and does not understand how
the shell has managed its job numbers.
None.
Shell Command Language ,
ps ,
wait() , the System
Interfaces volume of IEEE Std 1003.1-2001,
kill(), the
Base Definitions volume of IEEE Std 1003.1-2001,
<signal.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
