What is systemd ?

systemd is a suite of system management daemons, libraries, and utilities designed for Linux and programmed exclusively for the Linux API.

Systemd authors characterize the software suite as a “basic building block” for an Operating System.

The daemon systemd is the first process that is executed in user space during the Linux startup process.

systemd serves as the root of the user space’s process tree.

The name systemd adheres to the Unix convention of making daemons easier to distinguish by having the letter d as the last letter of the filename.