systemd is a software suite that provides an array of system components for Linux operating systems. Its main aim is to unify service configuration and behavior across Linux distributions; systemd's primary component is a "system and service manager"—an init system used to bootstrap user space and manage user processes. 

 

 

 

 

 

 

 

 

 

 

Indicators

• If you’re starting and stopping things using systemctl restart sshd, etc, you’re on a SystemD system.
• If you’re starting and stopping things using /etc/init.d/sshd start, etc, you’re on a SystemV system.