PowerShell Cmdlets: Internal Workings & Custom Implementations

• Table of contents

What Are PowerShell Cmdlets?

Cmdlets (short for Command-Lets) are lightweight, specialized commands in PowerShell that perform specific actions. Unlike traditional executable files (.exe) or scripts (.ps1), cmdlets are .NET classes that derive from the System.Management.Automation.Cmdlet or System.Management.Automation.PSCmdlet base class.

How Cmdlets Work Internally ?

A cmdlet follows a structured pattern:

• Inherits from the Cmdlet or PSCmdlet class.
• Implements one or more methods (ProcessRecord(), BeginProcessing(), EndProcessing()).
• Uses attributes like [Cmdlet()] to define its behavior.

Example of a simple custom cmdlet in C#:

using System.Management.Automation;

[Cmdlet(VerbsCommon.Get, "Message")]
public class GetMessageCommand : Cmdlet
{
    protected override void ProcessRecord()
    {
        WriteObject("Hello from a custom cmdlet!");
    }
}

This is compiled into a .dll and loaded into PowerShell via Import-Module.