PHP basename Function

last modified April 3, 2025

The PHP basename function extracts the filename component from a path string. It's useful for working with file paths in a cross-platform way.

Basic Definition

The basename function returns the trailing name component of a path. It takes two parameters: the path string and an optional suffix to remove.

Syntax: basename(string $path, string $suffix = ""): string. The function is binary-safe and works with both Unix and Windows paths.

Basic basename Example

This shows the simplest usage of basename to extract a filename.

basic_basename.php

<?php

declare(strict_types=1);

$path = "/var/www/html/index.php";
$filename = basename($path);

echo $filename; // Outputs: index.php

This extracts "index.php" from the full path. The function works the same regardless of the directory separator used in the input path.

Removing File Extension

The second parameter can remove a specified suffix from the result.

basename_suffix.php

<?php

declare(strict_types=1);

$path = "/var/www/html/index.php";
$filename = basename($path, ".php");

echo $filename; // Outputs: index

Here we remove the ".php" extension from the result. Note that the suffix must match exactly, including case sensitivity on case-sensitive filesystems.

Windows Path Example

basename works with Windows paths using backslashes.

windows_path.php

<?php

declare(strict_types=1);

$path = "C:\\Windows\\System32\\kernel32.dll";
$filename = basename($path);

echo $filename; // Outputs: kernel32.dll

The function correctly handles Windows-style paths. It returns "kernel32.dll" regardless of the directory separator style used in the input.

URL Path Example

basename can also extract the last component from URLs.

url_path.php

<?php

declare(strict_types=1);

$url = "https://example.com/images/logo.png";
$filename = basename($url);

echo $filename; // Outputs: logo.png

This extracts "logo.png" from the URL. Note that basename doesn't validate URLs - it just processes them as strings.

Multiple Directory Levels

The function works with paths containing multiple directory levels.

multi_level.php

<?php

declare(strict_types=1);

$path = "/home/user/docs/projects/php/README.md";
$filename = basename($path);

echo $filename; // Outputs: README.md

Despite multiple directory levels, basename correctly returns just "README.md". It only looks at the last path component.

Edge Cases

basename has some interesting behaviors with edge cases.

edge_cases.php

<?php

declare(strict_types=1);

$path1 = "/var/www/html/";
$path2 = "/var/www/html";
$path3 = "filename.txt";

echo basename($path1); // Outputs: html
echo basename($path2); // Outputs: html
echo basename($path3); // Outputs: filename.txt

With directory paths (ending with separator), it returns the directory name. For simple filenames, it returns the filename unchanged. Trailing slashes are ignored.

Best Practices

Validate Input: Check paths exist before processing.
Handle Encoding: Be aware of character encoding in paths.
Security: Sanitize input when using in filesystem operations.
Cross-platform: Use for both Unix and Windows paths.

Source

PHP basename Documentation

This tutorial covered the PHP basename function with practical examples showing its usage in different scenarios.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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