PHP-How to create a directory based on current year and current month ?

createdir.php

<?php

// - current year (for example : 2018)
$year=date('Y');

// - current month (for example : 12)
$month=date('m');

// directory path
$directory="./{$year}/{$month}/";

//  create directory , if directory doesn't exist
if(!file_exists($directory)){
    
    // creating directory 
    mkdir($dir,0777, TRUE);
    echo "Directory ( {$directory} ) created";
}

// directory already exists
else{
    echo "Directory ( {$directory} ) already exists";
}

?>