Powershell: Copy the content of the tag to another tag

hello. I want to copy the content of <title> tag and paste in the <meta keywords..> tag. Like a PARSING. And I don’t know why, I believe I do something wrong at line 9. Can anyone help me, please?

For example:
<title>MY TITLE</title>
<meta name="keywords" content="BEBE"/>

The output should be:
<title>MY TITLE</title>
<meta name="keywords" content="MY TITLE"/>

$sourcedir = "C:\Folder1"
$resultsdir = "C:\Folder2"

Get-ChildItem -Path $sourcedir -Filter *.html | ForEach-Object {
    $content  = Get-Content -Path $_.FullName -Raw -Encoding UTF8
    $keywords = ([regex]'<meta\s+name="keywords"\s+content="(.+?)"').Match($content)
    $title    = ([regex]'<title>.*?</title>').Match($content)
    if ($keywords.Success -and $title.Success) {
        $content = $content.Replace($keywords.Value, '<meta name="keywords" content="' + $title.Value + '"')
        $content | Set-Content (Join-Path $resultsdir $_.Name) -Force -Encoding UTF8
    }
}

You need to use a capture group so that you can strip out the title tags:

$sourcedir = "C:\Folder1"
$resultsdir = "C:\Folder2"

Get-ChildItem -Path $sourcedir -Filter *.html | ForEach-Object {
    $content  = Get-Content -Path $_.FullName -Raw -Encoding UTF8
    $keywords = ([regex]'<meta\s+name="keywords"\s+content="(.+?)"').Match($content)
    $title    = ([regex]'<title>(.*?)</title>').Match($content)
    if ($keywords.Success -and $title.Success) {
        $content = $content.Replace($keywords.Value, '<meta name="keywords" content="' + $title.Groups[1].Value + '"')
        $content | Set-Content (Join-Path $resultsdir $_.Name) -Force -Encoding UTF8
    }
}

thanks a lot @matt-bloomfield