Ubuntu - Services - Cheatsheet

Service-related commands

	systemd	SysVinit
Start a service	systemctl start service_name.service	service service_name start
Stop a service	systemctl stop service_name.service	service service_name stop
Restart a service	systemctl restart service_name.service	service service_name restart
Reload a service	systemctl reload service_name.service	service service_name reload
Service status	systemctl status service_name.service	service service_name status
Restart a service if already running	systemctl condrestart service_name.service	service service_name condrestart
Enable service at startup	systemctl enable service_name.service	chkconfig service_name on
Disable service at startup	systemctl disable service_name.service	chkconfig service_name off
Check if a service is enabled at startup	systemctl is-enabled service_name.service	chkconfig service_name
Create a new service file or modify configuration	systemctl daemon-reload service_name.service	chkconfig service_name --add

NOTE: New versions of systemd support systemctl start service_name etc.

	systemd	SysVinit
System halt	runlevel0.target,poweroff.target	0
Single user mode	runlevel1.target,rescue.target	1, s, single
Multi user	runlevel2.target, multi-user.target	2
Multi user with network	runlevel3.target, multi-user.target	3
Experimental	runlevel4.target, multi-user.target	4
Multi user with network and GUI	runlevel5.target, graphical.target	5
Reboot	runlevel5.target, reboot.target	6
Emergency shell	emergency.target	emergency
Change to multi-user runlevel	systemctl isolate multi-user.target	telinit 3
Set multi-user level for next boot	ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target	sed s/^id:.*:initdefault:/id:3:initdefault:/
Check current runlevel	systemctl get-default	runlevel
Change default runlevel	systemctl set-default multi-user.target	sed s/^id:.*:initdefault:/id:3:initdefault:/

	systemd	SysVinit
System halt	systemctl halt	halt
Power off the system	systemctl poweroff	poweroff
Restart the system	systemctl reboot	reboot
Suspend the system	systemctl suspend	pm-suspend
Hibernate	systemctl hibernate	pm-hibernate
Follow the system log file	journalctl -f	tail -f /var/log/messages or tail -f /var/log/syslog

Execute a systemd command on a remote host	systemctl service_name.service start -H user@host
Check boot time	systemd-analyze or systemd-analyze time
Kill all processes related to a service	systemctl kill service
Get logs for events for today	journalctl --since=today
Hostname and other host-related info	hostnamectl
Date and time of system with timezone and other info	timedatectl

systemctl mask system_name.service

Masking a service prevents the service from being started manually or automatically.

For this example, systemctl is creating a symlink from /etc/systemd/system/service_name.service to /dev/null.

Targets in /etc/systemd override those provided by packages in /lib/systemd.

systemd recognizes the symlink and will not start the service.