How to list all PHP variables in a file?

Question

I have a PHP file with PHP Variables inside.
Example:

Hi ,
Can you please send me an email ?

I would like to

Answer 1

Use file_get_contents() and preg_match_all():

$file = file_get_contents('file.php'); 
preg_match_all('/\$[A-Za-z0-9-_]+/', $file, $vars);

print_r($vars[0]);