PowerShell: Basic and new features
Basics
Concepts
shell: Historically, the term shell describes the piece of software that sits over an operating system’s core functionality. This core functionality is known as the operating system kernel.- f
Intro
cmd + .NET + C# = PowerShell
PowerShell syntax is aligned with C#. The major value this brings is PowerShell code can be migrated to C# when necessary for performance improvements, and, more importantly, C# examples can be easily converted to PowerShell
PowerShell is an Object-Oriented programming or scripting language, and it is based on .NET.
Windows is an API-driven operating system, compared to UNIX and its derivatives, which are document (or text) driven
PowerShell is an object-based shell. Everything in PowerShell has a type
It is best practice to reserve aliases for interactive usage and not use them in scripts.
The core PowerShell language is based on the mature IEEE standard POSIX 1003.2 grammar for the Korn shell, which has a long history as a successful basis for modern shells like Bash and Zsh
Version history
PowerShell v2 was a big release bringing modules, remoting, and jobs.
Subsequent releases have been as big in terms of their impact—PowerShell v3 brought PowerShell workflows and the CIM cmdlets;
PowerShell v4 brought Desired State Configuration;
and PowerShell v5 brought the ability to write classes in PowerShell.
The ForeachObject cmdlet now has a -Parallel switch that allows you to run script blocks in parallel
There are three new operator sets in PowerShell: the Ternary operator ( a ? b : c), the Pipeline chain operators ( | | and &&), and the Null coalescing operators (?? and ??=)
V2: modules, remoting, jobs
V3: workflow, CIM cmdlets
V4: Desired State Configuration
V5: class
V6: open source; .NET Core; Linux & Macos
V7: -Parallel in Foreach; new operators
WMI && CIM
WMI: Windows Management Instrumentation CIM: Common Information Model
PowerShell3.0以降、WMIの使用はもう推薦しない link