Linux is used in many different platforms like servers, phones, cars and embedded systems. Also many cloud services are backed by Linux. The technical quality and the fact that Linux is free of charge are the main reasons behind its success and popularity in many platforms. Linux based operating systems and free open source applications are also available to personal computing devices.
The up to date online learning material is developed by Linux Professional Institute. There are 16 main topics and after each one there is a small multiple choice exam that you use to evaluate your learning. For most topics there are also labs that help you to clarify the things learned in theory. The online material contains also a terminal window that is connected to Ubuntu-server. You use this connection to do the labs. The connection can also be used freely to your own experiments.
Besides the online studies there are teacher led workshops in computer class that help you achieve practical skills related to installing and configuring software to Linux based operating system. After the last workshop there is a supervised final exam.
See more about the workshops in Course Optima site