After you learn the commands in this chapter from Linux Phrasebook, 2nd Edition, you can start controlling your shell and finding out all sorts of interesting things about your files, folders, data, and environment.
This chapter from Docker Containers: Build and Deploy with Kubernetes, Flannel, Cockpit, and Atomic explains how to create a private Docker registry in Fedora or Ubuntu, use the docker-registry package, use the registry container image, and understand the Docker image namespace.
This chapter from CompTIA Linux+ / LPIC-1 Cert Guide: (Exams LX0-103 & LX0-104/101-400 & 102-400) covers Linux file system management as it pertains to the objectives on the CompTIA Linux+ / LPIC-1 exam.
Matthew Helmke looks at the options you have to manage your software in Ubuntu, including an introduction to the graphical software management tools that you will use for most of your software management. This chapter also covers monitoring and managing memory and disk storage on your system.