$ systemctl --version
$ whereis systemd
$ whereis systemctl

$ sudo systemctl reboot
$ sudo systemctl poweroff
$ sudo systemctl halt
$ sudo systemctl suspend
$ sudo systemctl hibernate
$ sudo systemctl hybrid-sleep
$ sudo systemctl rescue

Service Management

$ sudo systemctl start application
$ sudo systemctl start application.service
$ sudo systemctl restart application.service
$ sudo systemctl reload application.service
$ sudo systemctl status application.service
$ sudo systemctl stop application.service

$ sudo systemctl reload-or-restart application
$ sudo systemctl reload-or-restart application.service

$ sudo systemctl enable application
$ sudo systemctl enable application.service
$ sudo systemctl disable application.service

Checking for Specific States

$ systemctl is-active application
$ systemctl is-active application.service

$ systemctl is-enabled application.service

$ systemctl is-failed application.service

System State Overview

$ systemctl list-units
$ systemctl list-units --all
$ systemctl list-units --all --state=inactive
$ systemctl list-units --failed
$ systemctl list-units --type=service

$ systemctl status
$ sysystemctl status bluetooth.service
$ systemctl -H root@rhel7.example.com status httpd.service

$ systemctl is-active application.service  	 # Use in shell script 
$ systemctl is-failed application.service
$ systemctl is-enabled application.service

$ sudo systemctl start apache.service
$ sudo systemctl stop apache.service
$ sudo systemctl restart apache.service

$ sudo systemctl kill apache.service
$ sudo systemctl reload apache.service
$ sudo systemctl daemon-reload
$ systemctl show httpd.service
$ systemctl show -p CPUShares httpd.service
$ sudo systemctl set-property httpd.service CPUShares=500

$ systemctl list-dependencies nginx.service
$ systemctl list-dependencies --all nginx.service

$ cd /etc/systemd/system/
$ cd /usr/lib/systemd/system/

$ sudo systemctl enable clamd@scan.service
$ sudo ln -s '/usr/lib/systemd/system/clamd@scan.service' '/etc/systemd/system/multi-user.target.wants/clamd@scan.service'

$ sudo systemctl disable clamd@scan.service

$ systemctl list-unit-files
$ systemctl list-unit-files --type=service

Setting the Default Target

$ systemctl get-default
$ sudo systemctl set-default multi-user.target

Traditional runlevel      New target name     Symbolically linked to...
Runlevel 0           |    runlevel0.target -> poweroff.target
Runlevel 1           |    runlevel1.target -> rescue.target
Runlevel 2           |    runlevel2.target -> multi-user.target
Runlevel 3           |    runlevel3.target -> multi-user.target
Runlevel 4           |    runlevel4.target -> multi-user.target
Runlevel 5           |    runlevel5.target -> graphical.target
Runlevel 6           |    runlevel6.target -> reboot.target

Listing Available Targets

$ systemctl list-unit-files --type=target
$ systemctl list-units --type=target

Isolating Targets

$ systemctl list-dependencies multi-user.target
$ sudo systemctl isolate multi-user.target