wp.download.php

<?php
/**
 * Downloads latest WordPress and extracts it to script folder
 * @author Ruslanas Balčiūnas
 */

/* DELETE AFTER USAGE */

$fname = 'latest.tar.gz';
file_put_contents($fname, fopen('http://wordpress.org/latest.tar.gz', 'r'));

// remove old version
if(file_exists('latest.tar')) {
	unlink('latest.tar');
}

$p = new PharData($fname);
try {
	$p->decompress();
} catch (Exception $e) {
	die($e->getMessage());
}

try {
    $phar = new PharData('latest.tar');
    $phar->extractTo('./', null, true); // extract wordpress directory (overwrite)
} catch (Exception $e) {
    $e->getMessage();
}

unlink('latest.tar');
unlink($fname);

echo 'Done!';
?>