The Right Path - PHP

In addition to functions that allow you to obtain information on file sizes, permissions and modification times, PHP also offers a number of functions designed to manipulate file and path names, and split a file path into its constituent components. The two most commonly-used ones here are the basename() function, which returns the filename component of a path, and the dirname() function, which returns the directory name component of a path

The following example demonstrates the basename() and dirname() components in action, by splitting a file path into its constituents:

<?php

// set path

$path = "/usr/local/apache/bin/httpd";
// print filename

echo "File is " . basename($path) . "\r\n";
// print directory name

echo "Directory is " . dirname($path) . "\r\n";
?>

Here's the output:

File is httpd
Directory is /usr/local/apache/bin

You can also use the pathinfo() function to obtain this information - this function returns an associative array containing keys for directory name, file name and file extension. Take a look at this next script, which returns this information for the directory holding the currently executing script.

<?php

// parse current file path

$info = pathinfo($_SERVER['PHP_SELF']);
// print info

print_r($info);
?>

Here's the output:

Array
(
[dirname] => /dev/php
[basename] => fs.php
[extension] => php
)

Finally, you can use the realpath() function to translate relative paths into absolute ones, as below:

<?php

// returns /usr/local/lib

echo realpath("/usr/local/apache/bin/../../lib/");
// returns /lib

echo realpath("../../lib");
?>

You can obtain the script's current working directory by combining the
dirname() function with the special $_SERVER['SCRIPT_FILENAME'] variable,

<?php

echo "Current directory is " . dirname($_SERVER['SCRIPT_FILENAME']);
?>

or with the alternative getcwd() function, as below,

<?php

// get current working directory

echo "Current directory is " . getcwd();
?>

or even through creative use of the realpath() function, as below:

<?php

echo "Current directory is " . realpath(".");
?>