Use PHP to get the functions and server variables for the current url path

PHP gets the function and server variable of the current url path:
Code:

<?php
$path = /usr/opt/../ect/abcd;
echo $_SERVER['DOCUMENT_ROOT']."<br>";   // Get the server document root variable ( Depending on the http.conf The configuration in )
echo $_SERVER['PHP_SELF']."<br>";  // Gets the path to the file that executes the code, and http.conf The configuration in. 
echo __FILE__."<br>";  // Variable that gets the absolute path to the file system for the file 
echo dirname(__FILE__);  // Function to get the folder path of the file 
echo realpath($pah); 
?>

Value returned:

/usr/opt/apache2/htdocs/
/alias/aa.php
/usr/opt/apache2/htdocs/kamap/aa.php
/usr/opt/apache2/htdocs/kamap/
/usr/etc/abcd