SharePoint Script to update MMD Column in Library

This post contains the code to update Managed Metadata column value in Library.

Add-PSSnapin Microsoft.Sharepoint.Powershell
cls
#Log Variables
$basePath = split-path $SCRIPT:MyInvocation.MyCommand.Path -parent
Set-Location $basePath


#SP variables
$web=$null ;
$list=$null;
$SiteURL = "https://mysharepointsite/en-us"# Library Site Url
$ListName = "Pages";# List Name
$FieldName="Document"
$termStoreName = "Managed Metadata Service Application"
$termGroupName = "Document_Content"
$termSetName = "DocumentName"
$MMDValueToUpdate = "Technical Doc"


#Pre-requisite checks
Try
{
    #Web Check
    $web = Get-SPWeb $SiteURL
    if($web -eq $null)
    {
      Write-Host "Cannot find an SPSite object that contains the following Id or Url: $SiteURL"  $_.Exception.Message
       Exit
    }

    #List Check
    $list = $web.Lists[$ListName]
    if($list -eq $null)
    {

       Write-Host "Cannot find a List with the Name: $ListName in the web  "  $_.Exception.Message
       Exit
    }

  }

Catch
{
    Write-Host  "Unable to connect to the Site, Please check the Url . Failed with error : " + $_.Exception.Message
    Exit
}

if($list -ne $null)
{
try
{

 #Create a Taxonomy Session
 $TaxonomySession = Get-SPTaxonomySession -Site $web.Site
 $TermStore = $TaxonomySession.TermStores[$termStoreName]
 $TermGroup = $TermStore.Groups[$termGroupName]
 $TermSet = $TermGroup.TermSets[$termSetName]

 #Below line of code will get the name, GUID and other properties from TermStore
 $Term = $Termset.Terms[$MMDValueToUpdate]

#This is the Library Item OOTB ID of the item which you want to update
 $item = $list.GetItembyID($ItemID)
 if($item.Count -gt 0)
 {
 $MMSField = [Microsoft.SharePoint.Taxonomy.TaxonomyField]$item.Fields[$FieldName]
 #If value exists in TermStore
 if($Term)
 {
 $MMSField.setFieldValue($item,$Term)
 $Item.SystemUpdate()
 Write-Host "Updated value as: " $Term.Name -backgroundcolo Green
 }
 else
{
Write-Host "Could not find termstore properties for : " $MMDValueToUpdate  -backgroundcolo Red
}
}
catch
{
   Write-Host "Error : $_.Exception.Message" -foregroundcolor white -backgroundcolor Red
   return
}
}
else
{
   Write-Host "No List with Name "+$ListName

}