Adds record to hosts file

Add-RecordToHosts.ps1

# credit Tom Chantler: https://github.com/TomChantler/EditHosts
function Add-RecordToHosts
{
    [cmdletbinding()]
    param (
        [Parameter(Mandatory = $true, Position = 0)]
        [ValidatePattern('^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$')]
        [string[]] $DesiredIP,

        [Parameter(Mandatory = $true, Position = 1)]
        [ValidateNotNullOrEmpty()]
        [string[]] $Hostname,

        [Parameter(Position = 2)]
        [bool] $CheckHostnameOnly = $false
    )

    begin
    {
        $ErrorActionPreference = 'Stop'

        if (! ([Security.Principal.WindowsPrincipal][Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator"))
        {
            Write-Warning "Function requires elevation."
            Break
        }

        $hostsFilePath = "$($env:WinDir)\system32\Drivers\etc\hosts"
        $hostsFile = (Get-Content $hostsFilePath)

        Write-Verbose "Adding $desiredIP for $Hostname to hosts file"
    }
    process
    {
        $escapedHostname = [Regex]::Escape($Hostname)
        $patternToMatch = If ($CheckHostnameOnly) { ".*\s+$escapedHostname.*" } Else { ".*$DesiredIP\s+$escapedHostname.*" }

        if (($hostsFile) -match $patternToMatch)
        {
            Write-Host "$DesiredIp $Hostname - not adding; already in hosts file"
        }
        else
        {
            Write-Verbose "$DesiredIp $Hostname - adding to hosts file... "

            Add-Content -Encoding UTF8 $hostsFilePath ("`n$DesiredIP" + ' ' + "$Hostname") -NoNewLine

            Write-Host "Added."
        }
    }
}
#Add-RecordToHosts 8.8.8.8 www.google.com