title: Not able to update list field properties using sharepoint powershell
body: <p>How do I use PowerShell to update list field properties? When I try the following:</p>
  
  <pre><code>$site = Get-SPSite -Identity "http://vikas:26112/"
  
  $web= $site.OpenWeb()   
  
  $spList = $web.GetList("/Lists/Support Links") 
  $spFieldType = [Microsoft.SharePoint.SPFieldType]::Text
  $spList.Fields.Add("FirstName",$spFieldType,$false)
  $spList.Fields[“FirstName”].Description = “My FirstName Field”
  $spList.Fields[“FirstName”].Required=$true
  $spList.Fields["FirstName"].EnforceUniqueValues=$true
  $spList.update()
  
  $web.Dispose()  
  </code></pre>
  
  <p>After executing this <code>FirstName</code> field is added to list but properties of this field remains   unchanged:</p>
  
  <pre><code>Description =""  
  Required=false  
  EnforceUniqueValues=false  
  </code></pre>