nit.ps1

Param([switch]$l)

$raw = arp -a | Select-String 'dynamic'
[regex]$rgx = '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}'
[regex]$arprgx = '\w{2}-\w{2}-\w{2}-\w{2}-\w{2}-\w{2}'

$ips = $rgx.Matches($raw) | %{$_.Value}

$hosts = $ips | % {
  try{
    [System.Net.Dns]::GetHostByAddress($_)
  }catch{if($l){''}}
} | Select -Property HostName,AddressList

if($l){
  $arps = $arprgx.Matches($raw).Value
  $makes = $arps | % {
    try{
      Invoke-RestMethod -uri "http://api.macvendors.com/$_"
    }catch{''}
  }
  For ($i=0; $i -lt $hosts.Length; $i++){
    $hosts.Get($i) | Add-Member -NotePropertyName 'Vendor' -NotePropertyValue $makes.Get($i)
  }
  $hosts = $hosts | ?{$_.HostName -ne $null} | Sort -Property Vendor
}else{
  $hosts = $hosts | Sort -Property HostName
}

$hosts