# PowerShell find UPN of users in the given OU and create Exchange Mailbox with the alias == UPN
# If the mailbox already exists, the script errors on that entry.
# Author: Jonathan Haddock, following an example PS foreach script from Guy Thomas
# (http://www.computerperformance.co.uk/powershell/powershell_active_directory.htm)
# Version 1, August 2010, tested with WinSvr 2008 R2 Stnd and Exchange 2010 Stnd
$Dom = 'LDAP://OU=Dummy;OU=Students;OU=User;DC=bcgs;DC=local'
$Root = New-Object DirectoryServices.DirectoryEntry $Dom
$i=0
# Create a selector and start searching from the Root of AD
$selector = New-Object DirectoryServices.DirectorySearcher
$selector.SearchRoot = $root
$adobj= $selector.findall() |`
where {$_.properties.objectcategory -match "CN=Person"}
foreach ($person in $adobj){
	$prop=$person.properties
	$i++
	# In AD the property is userPrincipalName however, PS makes the attribute lower case, hence userprincipalname
	$upn = $prop.userprincipalname[0]
	# The UPN contains @ followed by the suffix, we only want the UPN prefix so we use split:
	$upnsplit = $upn.split("@")
	$alias = $upnsplit[0]
	# Output the alias to the screen:
	Write-host $alias
	# Enable the exchange mailbox
	Enable-Mailbox -Identity "$upn" -Alias "$alias"

	
}
"Total $i"