Powershell function similar to openssl -s_client to retrieve a certificate

Get-SSLServerCertificate.ps1

function Get-SSLServerCertificate {
    <# .SYNOPSIS
    Retrieves the X509 certificate by connecting to a SSL enabled server #>
    [Alias('s_client')]
    Param(
        # Hostname or IP address to connect to
        [Parameter(Mandatory)]
        [String]$Hostname,
        # Port to connect to
        [Parameter()]
        [Int]$Port = 443,
        # Save cert to file
        [Parameter()]
        [switch]$Save,
        # Don't output base64
        [Parameter()]
        [switch]$Quiet
    )

    $client = [Net.Sockets.TcpClient]::new($Hostname, $Port)
    $sslStream = [Net.Security.SslStream]::new($client.GetStream(), $false, { $true })
    $sslStream.AuthenticateAsClient($env:COMPUTERNAME)
    if ($Save) {
        [IO.File]::WriteAllBytes(
            [IO.Path]::Combine($pwd.Path, (
                ($sslStream.RemoteCertificate.Subject.replace('*', '_') -split ',|=')[1] + '.cer')),
            $sslStream.RemoteCertificate.GetRawCertData())
    }
    if (!$Quiet) {
        '-----BEGIN CERTIFICATE-----'
        [Convert]::ToBase64String(
            $sslStream.RemoteCertificate.GetRawCertData(),
            [Base64FormattingOptions]::InsertLineBreaks)
        '-----END CERTIFICATE-----'
    }
    $sslStream.Dispose()
    $client.Dispose()
}

With inspiration from https://gist.github.com/IISResetMe/66ab3f0ced4eb406f21bf354cfe7ad45

Updated version available in my HelperFunctions module.