Systemd is a system and service manager for Linux. In this post, I will document its basic usage.

Check if it is installed, or its version in your machine

systemctl --version

Yes, systemd providers the systemctl command. We always use the systemctl command to deal with our service.

The Man page

man systemd 

You can type this command in your Linux server to find the document of systemd

The directories

There are two important directories for systemd. One is /usr/lib/systemd/system, in which all the services are stored in. And another directory is /etc/systemd/system, which stored the service which will automatically start when the system starts. In general, The services stored in the second directory are a soft link to the first directory.

The systemctl command

systemctl [option] service-name

You can use the systemctl command to manipulate your service. This command has two arguments, the option which I will show below and the service name

The options

There are seral options for systemctl command:

  • start: start a service
  • stop: stop a service
  • restart: restart a service
  • reload: reload a service (in some cases, we need to make the new config take effect)
  • status: check the status of a service
  • is-active: check whether the service is active now.
  • is-enable: check whether the service starts automatically when the system boot.