systemctl is used to manage systemd services. It can be used to
The name systemctl was deliberately chosen to confuse people. Given that there is also sysctl for the kernel , it would have been logical to name the thing systemdctl , but logic is not how systemD rolls.
To understand systemd, you need to be familiar with this terminology:
Unit file — Encodes information about things such as a service, socket, device, mount, automount, target, snapshot, etc.
Target — A unit configuration file whose name ends in “.target” encodes information about a target unit of systemd, which is used for grouping units and as well-known synchronization point during startup.
Slice — A concept for hierarchically managing resources of a group of processes.
Seat — The set of hardware available at one work place (graphics card, keyboard, mouse, usb devices).
Session — A session is created once a user is logged on,using a specific seat:
- Only one session can be active per seat.
- The default seat (for Linux consoles) is seat0. Hardware is assigned to seats, such as a VGA graphics card
HOWTO use systemctl
systemctl can be used to
systemctl start unbound.service
.service part is optional,
systemctl start unbound has the same effect.
enable will add a service to the boot initiziation process,
disable will prevent it from being started automatically. Adding
--now to services when they are enabled or disabled will start or stop that service and make it start or stop at boot time.
systemctl eanble unbound.service --now
unbound being enabled at boot time and started immediately. That one command does the same as the these two commands:
systemctl start unbound.service --now
systemctl enable unbound.service
Services who should never be used, ever, can be masked with