General Information

kill is the command to send signals to processes.


  • Distro(s): Any

Kill Signals

List kill signals

kill -l

Some of the more often used signals:

Signal # Signal Name Description Can process ignore?
1 HUP Hangup (daemons re-read config file) Yes
9 KILL Kill immediately, kernel level No
15 TERM Software termination request, process cleans up and exits (default) Yes

Kill Syntax

kill [-signal] pid
  • -signal : can be the signal number or name
  • pid : process id of the target

If -signal is ommited, kill sends -15 (TERM) by default.

Kill Examples

Ask apache to re-read its configuration file after changes have been made. (Assumes httpd is pid 2123)

kill -1 2123


kill -HUP 2123

Ask apache to terminate gracefully:

kill 2123

Tell the kernel to immediately kill apache:

kill -9 2123


Kill process by name (instead of PID)

pkill httpd
  • Kills all process ids named httpd, sending signal 15 (SIGTERM)

Remove a user's ssh session (kick user off system)

pkill -u rjones sshd

Kill all processes started from a specific terminal

pkill -t pts/1
  • This does NOT kick them off the system, only kills their running programs started from that session.

  • linux_wiki/kill.txt
  • Last modified: 2019/05/25 23:50
  • (external edit)