List files in a specific directory, in a pattern based.

list_files.php

<?php
$link = '';
$pattern = "*.pdf";

function mountLink(string $file, string $link, string $ext = '.pdf') :string
{
    return "<a href=\"{$link}{$file}\" target=\"_blank\">" . str_replace($ext, '', $file) . "</a>\n";
}

foreach (glob($pattern) as $file) {
    echo mountLink($file, $link);
}