How can PHP be used to sort files by date in a directory?

To sort files by date in a directory using PHP, you can use the `scandir()` function to retrieve a list of files in the directory, then use `filemtime()` to get the last modified time of each file and sort the files based on this timestamp.

$dir = "/path/to/directory";
$files = scandir($dir);
usort($files, function($a, $b) use ($dir) {
    return filemtime($dir . "/" . $a) < filemtime($dir . "/" . $b);
});

foreach($files as $file) {
    echo $file . "<br>";
}