When it comes to managing system services, a Linux system administrator can choose between the classic init [1] and the relatively new systemd [2]. These utilities form a meeting ground for mature technology and new concepts.

Post-Boot

Directly after booting the kernel, a service will start and then accompany the rest of the system's ongoing operation and shut down. Throughout, this service is assigned the Process ID 1.

You can use ps on a running system to determine which program executes the administration of services. (See the instructions in the "Determining Process 1" box.)Whatever the result, you may be misled because of a possibly existing downward-compatible invocation, which may have convinced you that init is performing this task when it is indeed systemd.

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