systemd is a suite of basic building blocks for a Linux system. It provides a system and service manager that runs as Process ID 1 and starts the rest of the system.
To manage the services run the following commands:
systemctl list-units: This command lists the running units.
systemctl --failed: This command lists failed units.
systemctl list-unit-files: This command lists all the installed unit files. The unit files are usually present in /usr/lib/systemd/system/ and /etc/systemd/system/.
systemctl status pid: This command displays the cgroup slice, memory and parent for a PID.
systemctl start unit: This command starts a unit immediately.
systemctl stop unit: This command stops a unit.
systemctl restart unit: This command restarts a unit.
systemctl reload unit: This command asks a unit to reload its configuration.
systemctl status unit: This command displays the status of a unit.
systemctl enable unit: This command enables a unit to run on startup.
systemctl enable --now unit: This command enables a unit to run on startup and start immediately.
systemctl disable unit: This command disables a unit and removes it from the startup program.
systemctl mask unit: This command masks a unit to make it impossible to start.
systemctl unmask unit: This command unmasks a unit.
To get an overview of the system boot-up time, run the following command:
To view a list of all running units, sorted by the time they took to initialize (highest time on top), run the following command: