<?php
$b = array(1, 1, 2, 3, 5, 8);
$arr = get_defined_vars();
// print $b
print_r($arr["b"]);
/* print path to the PHP interpreter (if used as a CGI)
* e.g. /usr/local/bin/php */
echo $arr["_"];
// print the command-line parameters if any
print_r($arr["argv"]);
// print all the server vars
print_r($arr["_SERVER"]);
// print all the available keys for the arrays of variables
print_r(array_keys(get_defined_vars()));
?>