NAME

kill — terminate or signal a process

SYNOPSIS

kill	[-s signal_name] pid ...

kill	-l [exit_status]

kill	-signal_name pid ...

kill	-signal_number pid ...

DESCRIPTION

The kill utility sends a signal to the processes specified by the pid operands.

Only the super-user may send signals to other users' processes.

The options are as follows:

-s signal_name

A symbolic signal name specifying the signal to be sent instead of the default TERM.

-l [exit_status]

If no operand is given, list the signal names; otherwise, write the signal name corresponding to exit_status.

-signal_name

A symbolic signal name specifying the signal to be sent instead of the default TERM.

-signal_number

A non-negative decimal integer, specifying the signal to be sent instead of the default TERM.

The following PIDs have special meanings:

0

The signal is sent to all processes whose group ID is equal to the process group ID of the sender, and for which the process has permission.

-1

If superuser, broadcast the signal to all processes; otherwise broadcast to all processes belonging to the user.

-PGID

The signal is sent to all processes that belong to the specified process group ID (PGID).

Some of the more commonly used signals:

1

HUP (hang up)

2

INT (interrupt)

3

QUIT (quit)

6

ABRT (abort)

9

KILL (non-catchable, non-ignorable kill)

14

ALRM (alarm clock)

15

TERM (software termination signal)

Some shells may provide a builtin kill command which is similar or identical to this utility. Consult the builtin(1) manual page.

EXIT STATUS

The kill utility exits 0 on success, and >0 if an error occurs.

EXAMPLES

Terminate the processes with PIDs 142 and 157:

Send the hangup signal (SIGHUP) to the process with PID 507:

Terminate the process group with PGID 117:

SEE ALSO

builtin(1), csh(1), killall(1), ps(1), sh(1), kill(2), sigaction(2)

STANDARDS

The kill utility is expected to be IEEE Std 1003.2 (“POSIX.2”) compatible.

HISTORY

A kill command appeared in Version 3 AT&T UNIX in section 8 of the manual.

BUGS

A replacement for the command “kill 0” for csh(1) users should be provided.