What is PowerShell?
PowerShell is a mixture of a command line, a functional programming language, and an object-oriented programming language. PowerShell is based on Microsoft .NET, which gives it a level of open flexibility that was not available in Microsoft's scripting languages (such as VBScript or batch) before this.
PowerShell is an explorer's scripting language. With built-in help, command discovery, and with access to much of the .NET Framework, it is possible to dig down through the layers.
This book is based on PowerShell 5.1; some of the features discussed in the book may not be available in the earlier versions of PowerShell.