How to get current directory, filename and code line number in PHP

PHP provides large number of magical constants. These all constants are case sensitive. With the help of these constants, we can get current directory, filename, current line number and much more.

These are the some examples of PHP Magic Constants.

To get the current directory

__DIR__ : This constant is used to get the current directory of the file. This is equivalent to the dirname(__FILE__).

<?php echo "The current directory of this file is '" . __DIR__ . "'.\n"; ?>

Output: The current directory of this file is 'C:\wamp\www\demo'.

To get the current filename with full file path

__FILE__ : This is used to return the full file path and filename of the file.

<?php echo "The current file with path is '" .  __FILE__ . "'.\n"; ?>

Output: The current file with path is 'C:\wamp\www\demo\magic_const.php'.
This magic constant is mostly used in case where we have to include some files from the directory.

To get the current line number

__LINE__ : This is used to return the current line number of the file.

<?php echo "The line number of this code is '" .  __LINE__ . "'.\n"; ?>

Output: The line number of this code is '34'.
This constant is mostly used while debugging the code, or to get line number of the error.