Professional Windows® PowerShell for Exchange Server 2007 Service Pack 1

Chapter 1: Getting Started with Windows PowerShell

13

Optional and Required Parameters

Cmdlets may have some parameters that are not required to be used each time the cmdlet is run and are

considered optional. You will find that most cmdlets have at least some optional parameters, especially

cmdlets that modify items, because not all properties of an item require changing at the same time. This

allows you to use only the optional parameters necessary to make the desired changes while leaving out

all other optional parameters.

Then there are other parameters that must always be used when the cmdlet is run. You will find that

most cmdlets that take an action such as creating, modifying, or removing items have at minimum one

required parameter to identify the items on which to take action. If any required parameters are left out

when running a cmdlet, Windows PowerShell prompts the user to enter an input value for each of the

missing required parameters.

The

Identity parameter is one of the most common required parameters, typically used by cmdlets

that need as input the name of the object on which to take some action. For example, the

Set-User

cmdlet modifies attributes on an existing user account in the Active Directory directory service.

The

Identity parameter is required when using Set-User and is used to identify the user account

on which the changes are to be made. ...