kill

Terminate a program using the default SIGTERM signal

$ kill [process_id]

$ kill -l

$ kill %[job_id]

$ kill -HUP [process_id]

$ kill -INT [process_id]

$ kill -9 [process_id]

$ kill -STOP [process_id]

$ kill -SIGUSR1 -[group_id]

kill [-signal] pid...
kill -l

kill sends a signal to a process, usually to stop it. All signals except SIGKILL and SIGSTOP can be intercepted by the process to perform a clean exit. By default, SIGTERM is sent.

-l, -L, --table

List signal names and numbers

Specify signal to send

Specify signal by name or number (e.g., -9, -KILL, -SIGKILL)

Process ID to signal

Job ID from shell job control

SIGTERM (15): Request termination (default)
SIGKILL (9): Force immediate termination (cannot be caught)
SIGHUP (1): Hang up; often used to reload configuration
SIGINT (2): Interrupt (Ctrl+C)
SIGSTOP (19): Pause process (cannot be caught)
SIGCONT (18): Continue paused process

SIGKILL (-9) should be used as a last resort as it doesn't allow the process to clean up. Use SIGTERM first and give the process time to exit gracefully.

Part of standard Unix since early versions. The kill command has been available since Version 4 AT&T UNIX (1973).

killall(1), pkill(1), ps(1), signal(7)