We are looking to use Exchange 2007 and have been testing the Powershell.One thing I am concerned about is admin's ability to accidentally do more than they expected using powershell. For instance, they think they are setting a limit on a mailbox store, but the end up setting limits for all mailbox stores on the server.Is there any way to UNDO a command in Exchange Powershell? For instance, with Cisco, you could repeat the command but prefixed with a 'NO'.

Hi Bruce, There isnt any built-in command in Exchange 2007 Management Shell to undo last activity. In Cisco you might have standard set of command and programmed in hardware but Exchange Shell is the kind of programming language and you can extend it as much as you can imagine with your logic and make it very complex as per requirement to accomplish any task so its very difficult to undo it with a single command.

It is not possible to undo actions taken in Exchange Management Shell. For thisvery reason you should use WhatIf, Confirm and ValidateOnly parameters to your advantage and to avoid costly mistakes. You can read more about these parameters here: http://technet.microsoft.com/en-us/library/bb124088.aspx.