Find out from the machine name, what user is logged in

Question

thank you. Is there a way to find out from the machine name, what user is logged in or who the machine belongs to?
I can actually find out from the username what machine they have because there is a field called the wWWHomePage that gets populated with the computer name
how do I do that? 
Also I have a list of email addresses. How do I find the username from the list of email addresses ?
thanks

Answer 1

I have no good way to test this, so you'll probably have to adjust this on your end:
Get-Content .\users.txt | ForEach {
$emailAddr = $_
$props = @{
EmailAddress = $emailAddr
Username = ''
ComputerName = ''
ComputerPath = ''
try {
$userDetails = Get-ADUser -Filter "EmailAddress -eq '$emailAddr'" -Properties wWWHomePage -ErrorAction Stop
$pcDetails = Get-ADComputer -Identity $userDetails.wWWHomePage -Properties CanonicalName -ErrorAction Stop
$props.Username = $userDetails.SamAccountName
$props.ComputerName = $userDetails.wWWHomePage
$props.ComputerPath = $pcDetails.CanonicalName
} catch {
$props.Username = 'ERROR'
$props.ComputerName = 'ERROR'
$props.ComputerPath = 'ERROR'
New-Object PsObject -Property $props
} | Select EmailAddress,Username,ComputerName,ComputerPath
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