Item is not updating

Question

Hello
I have using small powershell script for updating item. In this script I do not want to add version and updating a title field. Whenever I run this script, first time it updates the title field, second time it  make it title field empty. Please
let me know what I am mising. I tested in different doc lib as well, but same result.
if ( (Get-PSSnapin -Name Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue) -eq $null )
{Add-PSSnapin Microsoft.SharePoint.PowerShell}
$WebURL = "http://vm-avi:15000"
$listName = "Shared Documents"
$web = Get-SPWeb -identity $WebURL
$list = $web.Lists[$listName]
$items = $list.items
#loop through SharePoint list
foreach($item in $items)
if($item["Title"] -eq "Avian")
$list.enableversioning=$false
$list.Update()
$item["Title"] = "Avian1"
#Update the item
$item.Update()
$list.enableversioning=$true
$list.Update()
$web.Dispose()

Answer 1

To update a list item without creating a new version, call .SystemUpdate instead of .Update.  Call .SystemUpdate($false) to not create a new version.
Something like:
if($item["Title"] -eq "Avian")
$item["Title"] = "Avian1"
#Update the item
$item.SystemUpdate($false)
See:
http://msdn.microsoft.com/EN-US/library/office/ms481195(v=office.15).aspx
Mike Smith TechTrainingNotes.blogspot.com
Books:
SharePoint 2007 2010 Customization for the Site Owner,
SharePoint 2010 Security for the Site Owner