Notes on Using Systemctl

Systemctl is an important utility for managing systemd-based systems. It is needed to unify service configurations and behaviour across Linux distros. ts primary component is a “system and service manager” – an init system used to bootstrap user space and manage user processes. It also provides replacements for various daemons and utilities, including device management, login management, network connection management, and event logging

Viewing Systemd Environment and Service Status

• Use systemctl show --property=[PROPERTY] to view a specific property of a service.
• Use systemctl status [SERVICE] to view the status of a service.
• Use systemctl list-units to list all units loaded in the system.

Installing and Managing Services with Systemctl

• Use apt install [systemD PACKAGE] to install a package.
• Use systemctl start [SERVICE] to start a service.
• Use systemctl stop [SERVICE] to stop a service.

Changing Service Parameters with Systemctl

• Use systemctl edit [SERVICE] to create/edit a drop-in unit configuration file.
• Use systemctl daemon-reload to reload daemon configuration files.
• Use systemctl restart [SERVICE] to restart a service after changes have been made.

Reverting a Service Parameter Change

• Stop the service with systemctl stop [SERVICE].
• Remove the config file with rm -rf (carefully) /etc/system.control/[SERVICE].
• Restart the service with systemctl deamon-reload and systemctl restart.

Example troubleshooting target.service

• Check what is wrong systemctl status target.service -l.
• Use preferred editor to edit the issue in the config file, vim in my case vim /etc/systemd/system/target.service.
• Fix the issue.
• Reload the service systemctl daemon-reload and systemctl start target.service
• Check if the issues resolved. systemctl status target.service
• Enable the service (in order for service to start when booting)systemctl enable target.service and reboot.