Understand precedence with PowerShell

There are many ways to create functionality in PowerShell including basic cmdlets, aliases and functions. When you use multiple combinations its important to understand the precedence. This is best understood by walking through a basic example.

Firstly just run:

get-process

This will result in processes being displayed as expected.

Now lets create a function called get-process that lists child items.

function get-process { Get-ChildItem }

Now if you run get-process it will show child items so the function trumps the built-in cmdlet.

Now let’s create an alias so get-process points to get-service.

New-Alias get-process -Value get-service

Run get-process and it shows services so an alias trumps a function (which trumps the native cmdlets).

Note, you can always force running the cmdlet by its full name.

microsoft.powershell.managementget-process

Once you’ve finished you can reverse by deleting one-at-a-time.

get-process

function get-process { Get-ChildItem }

New-Alias get-process -Value get-service

Remove-Item Alias:get-process

Remove-Item Function:get-process

 

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