Bulk Delete SharePoint Site Users with PowerShell

Below is a PowerShell script for deleting a filtered list of users from a SharePoint site.  Simply copy the script to a .ps1 file, adjust the $SITEURL to the url of the site and adjust the $USERNAMEFILTER to a lowercase string that is contained in all of the usernames you would like to delete.

The script is based on a combination of the scripts from:

http://blogs.msdn.com/b/vijgang/archive/2009/04/26/powershell-script-to-remove-all-users-from-a-sharepoint-group.aspx

and

http://nikspatel.wordpress.com/2010/08/10/delete-orphaned-ad-users-from-the-site-collection/

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[System.Reflection.Assembly]::Load("Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c")
[System.Reflection.Assembly]::Load("Microsoft.SharePoint.Portal, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c")
[System.Reflection.Assembly]::Load("Microsoft.SharePoint.Publishing, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c")
[System.Reflection.Assembly]::Load("System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")

###########################
# "Enter the site URL here"
$SITEURL = "http://demo2010a:2114"

# "Enter the username filter (lowercase) here"
$USERNAMEFILTER = "member"

###########################

$site = new-object Microsoft.SharePoint.SPSite ( $SITEURL )
$web = $site.OpenWeb()
"Web is : " + $web.Title

$usersToDelete = @()

# Iterate through the site's users and add usernames to
# an array of users to delete if the name contains
# contains the username filter.
foreach ($user in $web.SiteUsers)
{
	if ($user.LoginName.ToLower().Contains( $USERNAMEFILTER ))
	{
		$usersToDelete += $user.LoginName
	}
}

# Delete each user selected from the SiteUsers array.
# The SiteUsers array can't be iterated through directly
# as it gets changed as users are removed from it.
foreach ($user in $usersToDelete)
{
	"Removing user : " + $user
	$web.SiteUsers.Remove($user);
}

$web.Update();

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