Get-Member (Alias: gm)

When working with PowerShell, it is crucial to understand the properties and methods of objects you are dealing with. One of the most useful cmdlets for this purpose is Get-Member. This cmdlet provides insights into the structure of objects, allowing users to interact effectively with them.

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1. What is Get-Member, and Why is it Important?

Definition

Get-Member is a cmdlet in PowerShell that reveals the properties, methods, and events available on an object. Each object in PowerShell is based on a .NET class, and Get-Member allows users to inspect these objects to understand their capabilities.

Why Use Get-Member?

• When working with unfamiliar objects, Get-Member helps identify the available properties and methods.

• It enables users to discover how they can manipulate or retrieve data from an object.

• It is useful when troubleshooting scripts, as it provides a clear view of what an object contains.

Example

Get-Process | Get-Member

This command retrieves a list of running processes and pipes them into Get-Member. The output displays:

• The type/class name (System.Diagnostics.Process)

• The list of properties and methods available for process objects.

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2. How Get-Member Works

Basic Functionality

Whenever an object is piped into Get-Member, it inspects the first object in the pipeline and returns:

1. The type or class name of the object.

2. The properties and methods available for that object.

Example: Examining a Registry Item

$x = Get-Item HKLM:\
$x | Get-Member

• Get-Item HKLM:\ retrieves an item from the registry.

• Piping $x into Get-Member displays its available members.

This is useful when dealing with objects of unknown types.

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3. Using Get-Member with Different Object Types

Inspecting a Collection vs. an Item Inside a Collection

When working with collections (arrays, lists, etc.), it is important to differentiate between inspecting an individual item and inspecting the collection itself.

Example 1: Inspecting the First Item in a Collection

$output = Get-ChildItem C:\
$output | Get-Member

• This command retrieves items from C:\ (files and directories).

• Piping $output into Get-Member shows the members of the first item in the collection.

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Example 2: Inspecting the Collection Itself

Get-Member -InputObject $output

• Using -InputObject $output inspects the array itself (System.Object[]), revealing members like Count, Length, and SyncRoot.

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Understanding How Get-Member Handles Mixed Object Types

If multiple object types are piped into Get-Member, it does not list the members of every single object instance. Instead, it groups objects by type and displays the members for each unique type.

Example: Mixed Object Types

Get-ChildItem | Get-Member

• If Get-ChildItem returns a mix of files and directories, Get-Member will display members separately for System.IO.FileInfo and System.IO.DirectoryInfo.

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4. Alternative Ways to Use Get-Member

Using the -MemberType Parameter

To filter results, use the -MemberType parameter.

Get-Process | Get-Member -MemberType Property

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• This command displays only the properties of System.Diagnostics.Process.

Get-Process | Get-Member -MemberType Method

• This command displays only the methods of System.Diagnostics.Process.

Using the -Name Parameter to Search for a Specific Member

Get-Process | Get-Member -Name HandleCount

• This checks if HandleCount exists as a property or method.

Inspecting Static Members

[System.Math] | Get-Member -Static

• This displays static methods and properties of System.Math.