As an effect, organizations are making lot of investments in the above technologies and lot less in desktop applications. Considering all this even Microsoft has embraced open source whole heartedly.
This has led to less opportunities in .net stack and is not good news for .net software developers. Also an average .net developer is typically less familiar with opens source ecosystem. However now is the time to level up in the above technologies and since open source is rooted in Linux OS it’s a good to have friendship with Linux.
To give some idea, Linux as such is a Unix like operating system available in many flavours (distros), even the desktop environment on Ubuntu (a major distros) can be in two flavours GNOME or Unity. Its important to note that Linux servers in most cases run without a desktop environments, so a good command on CLI in imperative. A great first step or refresher for Linux is this resource.