systemd—yes, all lower-case, even at the beginning of a sentence—is the modern replacement for init and SystemV init scripts. It is also much more.
Standing just over 2 meters and hailing from о́стров Ратма́нова, Dasuberworm is a professional cryptologist, entrepreneur and cage fighter. When he's not breaking cyphers and punching people in the face, Das enjoys receiving ominous DHL packages at one of his many drop sites in SE Asia.
