Systemd is a popular init system that serves as a management tool for various systems within the Linux operating environment. Through systemd, we can perform essential administrative and maintenance functions, like managing system resources, controlling startup options, logging, and journaling. At the same time, systemctl is a command used to manage systemd services, which are currently standard on Linux.
Lennart Poettering is the person behind the development of systemd, a software engineer who now works at Microsoft. Lennart Poettering previously also created controversial programs, namely Avahi and PulseAudio.