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

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

function Remove-Users-Group($group)
{
    Write-Log ("`t`t" + $group.Name)
    foreach ($user in $group.Users)
    {
        Write-Log ("`t`t`t" + $user.LoginName)
        $group.RemoveUser($user)
    }
}

function Remove-Users-Web($web)
{
    Write-Log ("`t" + $web.Url)

    foreach ($g in $web.Groups)
    {
        Remove-Users-Group $g
    }

    foreach ($w in $web.Webs)
    {
        Remove-Users-Web $w
    }
}

function Remove-Users-Site-Col($site)
{
    Write-Log $site.Url
    foreach ($w in $site.RootWeb.Webs)
    {
        Remove-Users-Web $w
    }
}

#$site = Get-SPSite $url
#Remove-Users-Site-Col $site
$web = Get-SPWeb $url
Remove-Users-Web $web