Get the absolute path of the file containing the code of the upper-level directory

echo __FILE__ ; // Get the absolute address of the current file, result: F:wwwtest.php
echo dirname(__FILE__); // Get the absolute directory where the current file is, result: F: www
echo dirname(dirname(__FILE__)); //Get the upper directory name of the current file, result: F:
?>

By the way, here is another function in PHP: chdir() function.

chdir() function Definition and usage The chdir() function changes the current directory to the specified directory.

If successful, the function returns true, otherwise it returns false.

Grammar chdir(directory) parameter description directory required. Specifies the new current directory. Example:

//Get the current directory
echo getcwd();
echo "";
// Change to the images directory
chdir("images");
echo "";
echo getcwd();
?>

Output: C:jbxue.commain C:jbxue.commainimages