A script to convert Windows SIDs to names

whatSID.ps1

<#
.SYNOPSIS
A script to convert SIDs to names
.Description
A script to convert SIDs to names
.PARAMETER inFile
A file containing SIDs (1 per line)
#>

param (
    [Parameter(Mandatory=$true)][ValidateScript({
        if( -Not ($_ | Test-Path) ){
            throw "Specified input file does not exist"
        }
        return $true
    })][System.IO.FileInfo]$inFile
)

Get-Content $inFile | ForEach-Object {
    $SID = New-Object System.Security.Principal.SecurityIdentifier($_)
    $objName = $SID.Translate([System.Security.Principal.NTAccount])
    $objName.Value
}