Originally published on zero2php.dev — part of the Zero to PHP course. View this lesson on the original site.
What “magic” means here
Magic constants change depending on where PHP is executing:
__LINE__— current line number__FILE__— full path of the current file__DIR__— directory of the current file
Example
<?php
declare(strict_types=1);
echo __FILE__, "\n";
echo __DIR__, "\n";
When this helps
Useful for debugging paths while you learn includes and autoloading later.
From Zero to PHP — PHP foundations: environment, syntax, and values