Check field Template Source value using sitecore powershell SPE

Use Case :Review

Suppose we have a custom rich text  and it has been sourced with custom component or css .This is added when developer creates template field in data template. The below code snippet can be used as part of your review and refactoring process to clean up sitecore items. 

Here is the quick pick..Check Source field of rich text is empy or null.

$targetTemplate    = Get-item 'master:/sitecore/templates/User Defined/Common/Data';
$templateFilter    = Get-Item "master:/sitecore/templates/System/Templates/Template Field";


Get-ChildItem $targetTemplate.FullPath -recurse 
| Where-Object { $_.TemplateName -eq $templateFilter.Name -and $_.type -eq 'Rich Text' -and $_["source"] -eq ''} 
| ForEach-Object {
    $_.Name
    $_.Type
    $_["Source"] 
}

Reference

http://sitecore.stackexchange.com/questions/203/unable-to-get-value-of-source-using-spe