Linux Administration for Nerds
Copyright 2018 Brian Davis - CC-BY-NC-SA
When I learned Linux in the 90s there was something called the initV system.
This was the set of scripts that handled booting up the computer and starting all the necessary services. Mainly you would interact with it to change the runlevel from console to GUI or to add something to the boot up sequence. In recent years most major distributions have swapped initV with systemd. There was a lot of uproar in the Linux community when this happened and I think the main complaint was that it was fixing something that wasn't broke. But I can say that adding things like network drives to your init boot up was a decidedly manual process and I think the main idea behind systemd was to make things like that easier.
If you are looking to start, restart or stop services you will need to use systemctl.
systemctl start <service name> systemctl restart <service name> systemctl stop <service name>
To enable or disable a service
systemctl enable systemctl disable
To find a list of services that are being loaded look in
With systemd the system log moved into journalctl. Just run it to see the latest
log. Of course
tail /var/log/syslog also work.