Find users in Active Directory where showInAddressBook attribute is not Null
Get-ADUser -filter * -Properties * | ? {$_.showInAddressBook -ne $null} | Select-Object CN,SamAccountName,showInAddressBook
Get-ADUser -filter * -Properties * | ? {$_.showInAddressBook -ne $null} | Select-Object CN,SamAccountName,showInAddressBook