SystemD is a popular init system and service manager for Linux operating systems. It is designed to centralize and standardize the way services are started and managed on a Linux system. While SystemD has been met with some controversy and debate within the Linux community, it has become the default init system for many major Linux distributions.

If you are running a Linux system and you are not sure whether you are using SystemD or not, there are a few easy ways to check.

One way to check if you are using SystemD is to use the ps command to view the process tree. Simply open a terminal and run the following command:

ps -p 1 -o comm=

If the output of the command is systemd, then you are using SystemD as your init system. If the output is something else, then you are not using SystemD.

Another way to check if you are using SystemD is to look for the existence of certain SystemD-specific files and directories. SystemD uses a number of specific directories and files for storing configuration and information about services. You can check for the presence of these directories and files by running the following commands:

ls /etc/systemd/system

If this command returns a list of files and directories, then you are using SystemD. If the command returns an error or no output, then you are not using SystemD.

Additionally, you can check the version of SystemD installed on your system by running the following command:

systemctl --version

This command will output the version of SystemD that is currently running on your system.

It is important to note that while SystemD has become the default init system for many Linux distributions, there are still some distributions that do not use SystemD. For example, distributions such as Devuan and Gentoo use alternative init systems.

In conclusion, if you are unsure whether you are using SystemD on your Linux system, you can easily check by using the methods outlined above. SystemD has become the standard init system for many Linux distributions, but it is always good to verify the init system being used on your particular system.