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kill

Send a signal to a process

command Process ManagementSystem Administration

Overview

Sends the specified signal to the specified process or process group. If no signal is specified, the TERM signal is sent, which normally kills processes.

Syntax

kill [OPTION]... PID...
kill -l [SIGNAL_NUMBER]

Common Options

-s SIGNAL, --signal SIGNAL

Specify the signal to send (name or number, e.g., -9 or -KILL). Defaults to SIGTERM.

-SIGNAL_NUM or -SIGNAL_NAME

Specify signal by number (e.g., -9) or name (e.g., -TERM). This is POSIX compliant.

-l, --list

List all known signal names, or convert a signal number to its name.

Common Signals:

1 (SIGHUP - Hangup), 2 (SIGINT - Interrupt), 9 (SIGKILL - Kill), 15 (SIGTERM - Terminate), SIGSTOP (Stop process), SIGCONT (Continue stopped process).

Examples

$ kill 12345

Sends the default SIGTERM (15) signal to process ID 12345, requesting it to terminate.

$ kill -9 54321

Forcibly terminates process ID 54321 using SIGKILL.

$ kill -SIGKILL 54321

Another way to forcibly terminate process ID 54321.

$ kill -l

Lists all available signal names.

$ kill -l 15

Prints the name of signal 15 (which is TERM).

$ kill -s SIGHUP 6789

Sends the SIGHUP signal to process ID 6789 (often to reload configuration).

$ kill -TERM $(pidof my_server)

Sends SIGTERM to the process ID returned by `pidof my_server`.

$ pkill -f process_name

(Related command) Kills processes whose name matches process_name. Uses SIGTERM by default.

$ killall nginx

(Related command) Kills all processes named nginx. Uses SIGTERM by default.

Related Commands

useradd

Create a new user or update default new user information

ps

Report a snapshot of current processes

top

Display Linux processes (dynamic)

pkill

Signal processes based on name and other attributes

killall

Kill processes by name

jobs

List active jobs

terminatestopprocesssignalkillpid