Linux is a kernel, the core part of an operating system. It is used in different distributions like Debian, CentOS, Fedora, etc. Ubuntu is an open-source operating system based on Debian. It can be installed in two ways - Ubuntu Desktop and Ubuntu Server. The desktop version provides a graphical user interface (GUI) and it that can replace other operating systems like Windows, and macOS. It can also run alongside these operating systems. This version is preferred for your personal machines. The server version does not provide a GUI out-of-the-box, just a command line where you can enter text commands.
Professionals can opt for advanced courses to prepare for Linux certifications. Linux Foundation Certified System Administrator (LFCS) and Red Hat Certified System Administrator(RHCSA) courses help in preparing for the certification exams.
The playground gives you access to three different nodes. All three nodes can be accessed using the same terminal. Try out the basic Linux commands and experiment as much as you’d like. You can also refer to the Ubuntu documentation link provided in the playground.