PHP Manual . ... PHP 4 >= 4.0.4) get_defined_vars -- Returns an array of all defined variables . ... This function returns an multidimensional array containing a list of all defined variables , be them environment, server or user- defined variables . $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 ...