Continuation to How to use taxonomy hidden field article?

Example PowerShell script to update taxonomy(MMD) hidden field

Add-PSSnapin Microsoft.Sharepoint.Powershell

$sourceWebURL = "http://siteurl"
$sourceListName = "List Name"


$spSourceWeb = Get-SPWeb $sourceWebURL $spSourceList = $spSourceWeb.Lists[$sourceListName]

$spQuery = New-Object Microsoft.SharePoint.SPQuery
$caml = '<Where><Geq><FieldRef Name="ID" /><Value Type="Text">0</Value></Geq></Where>'
$spQuery.Query = $caml
$spSourceItems = $spSourceList.GetItems($spQuery)

$spSourceWeb.AllowUnsafeUpdates = "true";

foreach($item in $spSourceItems) {
    $item[taxonomyFieldObject.TextField] = "Term Value1|GUID1";
    # Based on how you have configured the MMD column, supply the input here. To check the hidden value, we can use sharepoint manager complex tool

$spSourceWeb.AllowUnsafeUpdates = "false";