Many cmdlets that are used regularly have default, or built-in, aliases assigned to them. These built-in aliases help reduce the typing that you have to do when you administer Exchange 2007 by using the Exchange Management Shell.

For example, the Get-ChildItem cmdlet resembles the MS-DOS Dir command. Because you are familiar with the Dir command, you might want to use the Dir alias when you use the Exchange Management Shell instead of typing Get-ChildItem every time that you want to view the contents of a directory. The output from the Get-ChildItem cmdlet and the Dir alias is the same and can be used interchangeably.

Table 1 shows the built-in aliases and their full names.

Table1   Built-in aliases

For more information about aliases, run the following command in the Exchange Management Shell:

Get-Help About_Alias

In addition to the default, or built-in, aliases, you can define and use custom aliases instead of the names of cmdlets that you frequently use. You can use the Set-Alias cmdlet to associate cmdlets to familiar command names that have the equivalent functionality in Cmd.exe. You can assign multiple aliases to a single command. But each alias can only be assigned to a single command. For example, you can have three aliases Alias1, Alias2, and Alias3 that are assigned to the Move-Mailbox cmdlet. You could then use any of the three aliases to run the Move-Mailbox cmdlet. However, each alias that you create can only be assigned to the Move-Mailbox cmdlet. You can't, for example, assign Alias1 to both the Move-Mailbox cmdlet and the Get-Mailbox cmdlet.

To create a new alias-cmdlet pairing, run the Set-Alias cmdlet and supply the name of the alias, together with the name of the cmdlet that you want to call when the alias is entered.

Table 2 shows several examples of how to create a new alias.

Table 2   Examples of custom aliases

Set-Alias Type Get-Content

Set-Alias Dir Get-ChildItem

Set-Alias Erase Remove-Item

Set-Alias Pad "${env:programfiles}\Windows NT\Accessories\wordpad.exe"

Set-Alias Aliases Get-Alias

To remove an alias, delete the alias from the alias drive. For example, an administrator creates the Ls alias by using the following command:

Set-Alias Ls Get-ChildItem

Later the administrator decides that the Ls alias is no longer needed and uses the following command to remove the Ls alias:

Remove-Item Alias Ls

The Export-Alias cmdlet writes the current alias list to a file in comma-separated values (CSV) format. You can include the name of the file and its path in the command line. If the path doesn't exist, the cmdlet will create the path for you. You can create the file by using the .txt or .doc extensions.

The Import-Alias cmdlet reads a text file that has CSV values and brings the list into the Exchange Management Shell as an object. By using the Export-Alias cmdlet and Import-Alias cmdlet, you can export a list of aliases from the Exchange Management Shell on one computer and import them to the Exchange Management Shell on another computer. Because existing predefined aliases exist on both computers, all alias name conflicts will be ignored and not imported.

Aliases that are created from the command line by using the Set-Alias cmdlet during an Exchange Management Shell session can be used when the session is active. After the session is closed, the alias definition is lost. To make a user-defined alias persistent and available every time that a new Exchange Management Shell session is opened, you must add the alias definition to the Exchange Management Shell Microsoft.PowerShell_Profile.ps1 file that is located in the My Documents\PSConfiguration subfolder of your user profile directory.

Although aliases can be defined for cmdlets and used instead of cmdlet names, you can't include parameters in the definition of the aliases that you define. You must provide parameters as needed when the alias is called, exactly as you would if you called the cmdlet.