The systemctl command is used to interact with systemd and can be used to list systemd unit information and manage services.
NOTE that this is different from the sysctl command.
MANAGING SERVICES
1. List manageable services
List all service units with the command:
# systemctl list-units --type service
2. Starting a service
Upstart Command: ‘service crond start’. The equivalent Systemd command is:
# systemctl start crond.service
3. Checking the status of a service
Upstart Command: ‘service crond status’. Systemd Equivalent:
# systemctl status crond.service
4. Stopping a service
Upstart Command: ‘service crond stop’. Systemd Equivalent:
# systemctl stop crond.service
5. Start service on boot
Upstart Command: ‘chkconfig crond on’. Systemd Equivalent:
# systemctl enable crond.service
6. Do not start service on boot
Upstart Command: ‘chkconfig crond off’. Systemd Equivalent:
# systemctl disable crond.service
MANAGING TARGETS(RUNLEVELS)
The table below indicates the target names for each SysVinit/Upstart ‘runlevel’
| Runlevel | Target Units |
|---|---|
| 0 | poweroff.target |
| 1 | rescue.target |
| 2 | multi-user.target |
| 3 | multi-user.target |
| 4 | multi-user.target |
| 5 | graphical.target |
| 6 | reboot.target |
1. List Runlevels/Targets
List all target units with the command:
# systemctl list-units --type target --all
2. Print the default target
# systemctl get-default
3. Change Runlevels/Targets
Change the default target to ‘runlevel 3’:
# systemctl set-default multi-user.target
Switch to ‘runlevel 3’:
# systemctl isolate multi-user.target
