PowerShell: Object Type, Properties, Methods

By Xah Lee. Date: 2021-05-25. Last updated: 2022-09-05.

PowerShell commands input (parameter args) and output are all .NET objects. Each .NET object has a type, and members (“member” means properties and methods.). It's critical to understand this to master PowerShell.

A command may output multiple objects.
Each object has a type.
The number of objects and type depends on the command parameter. For example, dir -name may return many objects but all of type System.String, but dir may return many objects, some of type System.IO.FileInfo, some of type System.IO.DirectoryInfo.

PowerShell help dir 2021-05-25 ZY62f — `help dir`, showing types of its input and output.

Screenshot 2021-09-09 205739 zH7S7 — `help dir` output, showing the types of paramater args.

Find the Types of Command Output

To find the object types of a command's output, pipe it to Get-Member (alias gm). For each object type, Get-Member shows it only once in its output.

examples:

"abc" | Get-Member
# System.String

PowerShell get-member 2022-04-28 — get-member

dir | Get-Member
# System.IO.DirectoryInfo, System.IO.FileInfo

Get-Date | Get-Member
# System.DateTime

Get the Type of an Object

Get Object Type

List Properties of a Given Object Type

dir -file | Get-Member -MemberType Properties

PowerShell list properties 2022-04-24 — list properties

List Methods of a Given Object Type

dir -file | Get-Member -MemberType Method

PowerShell list methods 2022-04-24 — list methods

Show Property Values of a Object

Show all properties and their values of a object

Get-Date | select -Property *

dir -file | select -First 1 | select -Property *

select is alias of Select-Object