Microsoft's announcement of "open sourcing" .NET in 2014 almost stirred a storm. Many rushed to the stands (so to speak) to read about the unbelievable—how could Microsoft possibly open-source the core of their operating system? Some were cynical, others rejoiced. Then came the announcement a little louder and clearer that .NET Core was open source, not the .NET Framework. Many said .NET Core was a subset of .NET Framework.

.NET was first announced in 2000, as a new platform based on Internet standards. Along with it, by the end of the year, Microsoft published the Common Language Infrastructure as a standard, so that anyone who wanted, could write their own .NET framework based on those standards. .NET Framework has been the basis of Windows since the noughties.

Windows PowerShell was released to the general market in 2006, as an implementation of .NET Framework, focussed on system administrators (or sysadmins, to enable them to better manage their Windows workloads and automate tasks.

In June of 2016, Microsoft released a collaboratively refactored, more modern and efficient .NET. The .NET Core was officially born. While .NET Framework continues to rule the Windows arena, .NET Core, which is open source and cross-platform, has picked up great momentum and continues to grow. And .NET Core seems to be the way forward.

PowerShell (not Windows PowerShell) is based on .NET Core, and therefore, is open source, with the same vision as .NET Core to be cross-platform.

In this chapter, we will look at a very simple implementation of .NET Core and compare it to the output of PowerShell to prove that PowerShell is nothing but encapsulated .NET Core code. Along with it, we shall look at the general behaviour of PowerShell as well.