param(
    [Parameter(Mandatory=$true)]
    [string]$url
)

function Write-Log($msg)
{
    Write-Host $msg -foregroundcolor green
    ($msg) | Out-File "log-enum-users.txt" -Append
}

function ContainsUser($users, $loginName)
{
    foreach ($user in $users)
    {
        if ($user.LoginName.ToLower() -eq $loginName.ToLower())
        {
            return $true
        }
    }
    return $false
}

$users = New-Object System.Collections.ArrayList
$site = Get-SPSite $url
foreach ($user in $site.RootWeb.AllUsers)
{
	if ([System.String]::IsNullOrEmpty($user.Email))
	{
		$users.Add($user) > $null
	}
}
foreach ($user in $site.RootWeb.SiteUsers)
{
	$contains = ContainsUser $users $user.LoginName
	if ([System.String]::IsNullOrEmpty($user.Email) -and (-not $contains))
	{
		$users.Add($user) > $null
	}
}

foreach ($user in $users)
{
    Write-Log($user.LoginName)
}