Lander

$b = 300;
for ($i = 0; $i < 200; $i++) {
    $b = $b*20/100;
    echo $b;
}

$_ALL = [
    'SERVER' => $_SERVER,
    'GET' => $_GET,
    'POST' => $_POST,
    'FILES' => $_FILES,
    'COOKIE' => $_COOKIE,
    'SESSION' => $_SESSION,
    'REQUEST' => $_REQUEST,
    'ENV' => $_ENV
];

$login = $connection->query('SELECT * FROM `users`');

SELECT * FROM `users` WHERE `login` = 'login' AND `password` = 'pass';

Начал изучать php

function isNameInFile($name) {
    return in_array($name, file('/path/to/file')):
}
...
if(!$check['cnt'] && isNameInFile($name))  { 
    //регистрация 
}

$sku= 'KTL 190617';

$keys = array_keys(array_filter(
    $goods, 
    function ($goody) use ($sku) {
        return $goody['name_g'] == $sku;
    }
));

~40-60 файлов (.txt)