How do I get a file name from a full path with PHP?

You're looking for basename.

The example from the PHP manual:

<?php
$path = "/home/httpd/html/index.php";
$file = basename($path);         // $file is set to "index.php"
$file = basename($path, ".php"); // $file is set to "index"
?>

There are several ways to get the file name and extension. You can use the following one which is easy to use.

$url = 'http://www.nepaltraveldoor.com/images/trekking/nepal/annapurna-region/Annapurna-region-trekking.jpg';
$file = file_get_contents($url); // To get file
$name = basename($url); // To get file name
$ext = pathinfo($url, PATHINFO_EXTENSION); // To get extension
$name2 =pathinfo($url, PATHINFO_FILENAME); // File name without extension

I've done this using the function PATHINFO which creates an array with the parts of the path for you to use! For example, you can do this:

<?php
    $xmlFile = pathinfo('/usr/admin/config/test.xml');

    function filePathParts($arg1) {
        echo $arg1['dirname'], "\n";
        echo $arg1['basename'], "\n";
        echo $arg1['extension'], "\n";
        echo $arg1['filename'], "\n";
    }

    filePathParts($xmlFile);
?>

This will return:

/usr/admin/config
test.xml
xml
test

The use of this function has been available since PHP 5.2.0!

Then you can manipulate all the parts as you need. For example, to use the full path, you can do this:

$fullPath = $xmlFile['dirname'] . '/' . $xmlFile['basename'];