get_defined_vars

<?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 paramaters 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()));
?>