Course work from the Pluralsight course "Getting Started with Linux System Administration" by David Clinton.
https://app.pluralsight.com/library/courses/getting-started-linux-system-administration/
If you're looking to become more effective with system administration in Linux, this course might be just what you need. In this course, Getting Started with Linux System Administration, you'll be introduced to some Linux administration basics. First, you'll learn about monitoring and optimizing a Linux server. Next, you'll be configuring user accounts and groups to closely control access to resources. Finally, you'll explore how to harden your server by ensuring that your data is appropriately encrypted and network ports aren't unnecessarily left open. When you're done, you'll have Linux skills that can add value to a broad range of IT projects.