Powershell Set Operations

Set operations can do filtering, ordering,grouping and selecting operations on collection of objects that are passed to them.

Filtering (Where-Object)

The Get-Service cmdlet gets objects that represent the services on a computer. Now, I want to show you how to filter Get-Service result set.

Get-Service|Where-Object name -eq “MSSQLSERVER”

filtered result set

And these are synonyms:

Get-Service|Where name -eq “MSSQLSERVER”
Get-Service|? name -eq “MSSQLSERVER”

More than one criteria to add in filter.

Get-Service|Where-Object {$PSItem.Name -like “*sql*” -and $PSItem.Status -eq “Running”}

Ordering (Sort-Object)

We can sort Get-Servicecmdlet result set with sort-object.

Get-Service|Sort-Object name # sort by name
Get-Service|Sort-Object Status # sort by Status

We can use descending order.

Get-Service|Sort-Object -Descending Name

This is synonym of Sort-Object

Get-Service|Sort -Descending Name

Grouping(Group-Object)

We can group the Get-Service cmdlet with Group-Object.

Get-Service|Group-Object Status

grouped result set

Selecting(Select-Object)

We can select specified properties of a Get-Service cmdlet with Select-Object.

Get-Service|Select-Object Name

We can choose more than one properties.

Get-Service|Select-Object Name,ServiceType,Status

If you want to see first N record, you should use -First parameter. This sample shows us top 10 records.

Get-Service|Select-Object -First 10 Name,ServiceType,Status

If we want to show all properties we may use select * (like sql). In this sample we can see first record’s all properties.

Get-Service|Select-Object -First 1 *

The synonym is Select.

Get-Service|select Name,ServiceType,Status

All in one sample:

Get-Service|where name -like ‘M*’|sort Name|select -first 5 Name,Status,StartType|group-object Status

Below sample.It gets, name start with ‘M’ services then sort by Name properties and select first 5 records. At the end, it groups by Status property.