Before we start with the first chapter, we will very briefly discuss the content of this book and its aims. As you know, there are many PowerShell books out there, which also deliver very rich content. But it has been our experience that some topics are missing in most of them. In addition, we recognized new topics, especially coming with the new PowerShell Core v6, but also by addressing more and more security topics and targeting enterprise environments.

Therefore, we want to introduce PowerShell in terms of all of the topics targeting enterprise companies, such as PowerShell Security, Centralization, Release Pipelines, Just Enough Administration (JEA), and more, but also in terms of completely new topics arising from PowerShell Core 6 and the new editing tool, Visual Studio Code. The intention, overall, is to deliver a solid PowerShell book that is a useful resource for beginners, but is also packed full of completely new and reworked content, which even PowerShell professionals might benefit from.

Today, we have a broad number of PowerShell versions available, starting with PowerShell 1 up to the Windows PowerShell 5.1, PowerShell Core 6, and even the PowerShell in Azure Cloud Shell. Most enterprise companies primarily work with PowerShell versions starting from 2 up to 5.1. But, what PowerShell version should you use, and how can each of them be installed and made available? This is what the first chapter is about; its aim is to give you some background information and a good overview of all currently available PowerShell versions, how to install them, and how to use them.

These are the topics we'll be covering in this chapter:

• Historical background
• Overview of different versions of PowerShell
• Windows PowerShell 5.1
• Upgrading to the latest PowerShell version in Windows environments
• PowerShell Core v6
• Differences between Windows PowerShell and PowerShell Core v6
• PowerShell open source
• Goals of PowerShell Core v6
• PowerShell in Azure Cloud Shell
• Future of Windows PowerShell
• How to contribute to the open source project