SharePoint Web Id using PowerShell

Get SharePoint Web Id using PowerShell

1. Open SharePoint 2010 management Shell (PowerShell) with administrator privileges

2. Execute following command

$site =  Get-SPSite "http://yoursite"
$web = $site.AllWebs["Web Display Name"]
#For root web
#$web = $site.RootWeb
$web.ID

3. Above script will show unique id of the web