Microsoft.PowerShell.Crescendo overview

PowerShell, like other shells, is capable of invoking command-line tools. However, it would improve the experience if the command-line tool could participate in the PowerShell pipeline and take advantage of the parameter behaviors that are part of PowerShell.

Crescendo provides a framework to rapidly create PowerShell cmdlets that amplify command-line tools, regardless of platform. The goal of a Crescendo-based module is to create PowerShell cmdlets that use a command-line tool and, unlike that tool, return PowerShell objects instead of plain text.

How Crescendo works

The Crescendo framework has two main components:

  • A JSON configuration file that describes the cmdlets you want
  • Output handler functions that parse the output from the command-line tool and return objects

The Crescendo module provides cmdlets to help you create the JSON configurations and build a module containing the cmdlets you defined. You must write your own output handler functions that return PowerShell objects.

Crescendo-specific terminology

The documentation for Crescendo includes some new terminology.

  • command-line tool - a native executable file installed on your system
    • For example: ipconfig.exe
  • command - what you type on the command line to invoke the executable, which may include specific parameters
    • For example: ipconfig.exe /all
  • amplified command - the cmdlet you created with Crescendo to wrap a command in a PowerShell function
    • For example: Get-IpConfig -All

The Crescendo configuration file schema

When you author a Crescendo configuration file, you're writing JSON. For convenience,validation, and an improved developer experience, a schema file is available.

You can review the schema to see the required and optional configuration settings, their descriptions, and the value types they accept. When you author your configuration file in Visual Studio Code, you get numerous helpful features, including IntelliSense, validation while you edit, and more.