Update GAL Display Name - powershell

We recently decided to change on how our Global Address list is displayed from using the format to the , format.

Powershell made quick work of this task and took about 10 minutes with 2500 users. Here's the script.

###=====================================
### Update Exchange Global Address List Display
### - Matt Brown, 2008
###=====================================
$Users = Get-User -ResultSize unlimited |
 where {
   ($_.RecipientTypeDetails -eq "MailUser")
   -or ($_.RecipientTypeDetails -eq "UserMailbox")
 }

ForEach ($Person in $Users) {
   $NewName = $User.LastName + ", "
   $NewName += $User.FirstName + " "
   $NewName += $user.Initials
  
   # get rid of trailing spaces caused by blank initials
   $NewName = $NewName.Trim()
   Set-User $User -Name $NewName -DisplayName $NewName
   $NewName = $Null
}

Don't forget to update the OAB after this is done so your outlook clients will update.