active directory - Powershell - User creation script avoid duplicate username -

i ad search using powershell discover if username want create in use,. if in use want script add following number @ , of user name.

import-module activedirectory     $family= mclaren     $first= tony     #this part of script use first 5 letters of $family , first 2 letters of $first , join them give $username of 7 letters     $username = $family.substring(0, [math]::min(5, $family.length)) + $first.substring(0, [math]::min(2, $first.length))  

• the user name "mclarto" base on (username take 5 first letters of family name plus 2 charof firstname) seach done in ad.
• if there no result, "mclarto" taken $username without number @ end.
• if search find other users same username, username should take following number, in case "mclarto1".
• if "mclarto1" exist "mclarto2" should use , on.

the answer have propose david martin there, there part if username don't exist, i don't want $username contain number if it's unique.

thanks

i think close, uses activedirectory module.

import-module activedirectory  $family = "mclaren*"  # users matching search criteria $matchingusers = get-aduser -filter 'userprincipalname -like $family'   if ($matchingusers) {     # array of usernames splitting on @ symbol     $matchingusers = $matchingusers | select -expandproperty userprincipalname | %{($_ -split "@")[0]}      # loop around each user extracting numeric part     $usernumbers = @()     $matchingusers | % {          if ($_ -match '\d+')         {             $usernumbers += $matches[0]         }     }      # find maximum number     $maxusernumber = ($usernumbers | measure-object -max).maximum      # store result adding 1 along way (probably worth double checking doesn't exist)     $suggestedusername = $family$($maxusernumber+1) } else {     # no matches use name     $suggestedusername = $family }  # display results write-host $suggestedusername