Exchange 2007 Shell has three pre-defined variables that it loads into a shell console by default.
They are $exbin, $exinstall and $exscripts
$exbin has the path to the Bin directory of exchange 2007.
$exinstall has the exchange 2007 install path
$exscripts has the exchange 2007 scripts folder path, which we commonly use.
Where are these variables defined?
When a shell console is loaded, it runs a script called Exchange.ps1 which is stored in the Bin directory.