====== kill ======

**General Information**

kill is the command to send signals to processes.

**Checklist**
  * Distro(s): Any

----

====== Kill Signals ======

List kill signals
<code bash>
kill -l
</code>
\\

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 ======
<code bash>
kill [-signal] pid
</code>

  * -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)
<code bash>
kill -1 2123
</code>

or

<code bash>
kill -HUP 2123
</code>

Ask apache to terminate gracefully:
<code bash>
kill 2123
</code>

Tell the kernel to immediately kill apache:
<code bash>
kill -9 2123
</code>

----

====== pkill ======

Kill process by name (instead of PID)
<code bash>
pkill httpd
</code>
  * Kills all process ids named httpd, sending signal 15 (SIGTERM)

\\
Remove a user's ssh session (kick user off system)
<code bash>
pkill -u rjones sshd
</code>

\\
Kill all processes started from a specific terminal
<code bash>
pkill -t pts/1
</code>
  * This does NOT kick them off the system, only kills their running programs started from that session.

----