Powershell - Loop through sub directories and look for and rename file

gistfile1.txt

$targDir = "C:\inetpub\websites\ADA*\";
$subDir = $(Get-ChildItem "$targDir");


foreach($sub in $subDir) {
    $files = $(Get-Childitem $sub -Filter app_offline*.htm);

    foreach($file in $files) {
        $oldname = $file.FullName;
        $newname = $oldname.Replace("_.htm", ".htm");

        if ($newname.IndexOf(".htm") -gt 0) {
            $oldname;
            $newname;

            Rename-Item $oldname $newname;
        }
    }
}