update-m3u.ps1

# 
# Update all m3u files
# Arguments: working directories
# 
$extensions = @(".mp3", ".m4a", ".flac")
$Args | % {
    ls -r $_ | ? { $_.Extension -eq ".m3u" } | % {
        $listfile = $_
        pushd $listfile.Directory
        "#EXTM3U" | Out-File $listfile -Encoding utf8
        ls -r $_.Directory |
            ? { $extensions.Contains($_.Extension.ToLower()) } |
            sort { $_.FullName } |
            % { Resolve-Path -Relative $_.FullName } |
            % { $_.Replace("\", "/") } |
            Out-File -Append -Encoding utf8 $listfile
        popd
        echo $listfile.FullName
    }
}