Kill (Unix)

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 POSIX.1-2017 called with the following arguments: The value of the pid operand shall be used as the pid argument. The kill utility shall conform to XBD Utility Syntax Guidelines , [XSI) ] ![[Option Start]]( except that in the last two SYNOPSIS forms, the - signal number and - signal name options are usually more than a single character. ![[Option End]]( Specify the signal to send, using one of the symbolic names defined in the 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 The effects of specifying any signal number other than those listed below are undefined. Provide a default value for the internationalization variables that are unset or null. (See XBD Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.) If set to a non-empty string value, override the values of all the other internationalization variables. Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error. [XSI) ] ![[Option Start]]( Determine the location of message catalogs for the processing of LC MESSAGES. ![[Option End]]( When the -l option is not specified, the standard output shall not be used. At least one matching process was found for each pid operand, and the specified signal was successfully processed for at least one matching process. the kill operates in a different environment and does not share the shell's understanding of job numbers. 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 POSIX.1-2017 and this volume of POSIX.1-2017 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: 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 also required symbolic signal name s 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 name s. Since neither applications portability nor ease-of-use would be improved by requiring this extension, it is no longer required. The -s option was added in response to international interest in providing some form of kill that meets the Utility Syntax Guidelines. the kill operates in a different environment and does not understand how the shell has managed its job numbers. The obsolescent versions of the SYNOPSIS are t