dirname()

PHP dirname() Function

The dirname() function returns the parent directory portion of a path. Given a full path to a file or directory, it strips off the trailing component and gives you the directory that contains it. This page covers the syntax, the $levels parameter, edge cases, and how dirname() differs from related path functions.

It's a pure string operation: dirname() parses the text of the path you pass in. It does not touch the filesystem, so the path doesn't have to point at a file that actually exists.

Syntax

dirname(string $path, int $levels = 1): string

• $path — the path to operate on (required).
• $levels — how many directory levels to go up. Defaults to 1. Available since PHP 7.0; must be 1 or greater.

It returns the parent directory of $path as a string.

Parameters

Examples

Get the directory of a file

This retrieves the directory that contains example.txt:

Output:

/home/user1

Get the parent of a directory

A trailing slash is treated as the end of a directory name, so dirname() still returns the parent:

Output:

/home/user1

Climb multiple levels with $levels

Pass a second argument to go further up the tree in one call:

<?php

echo dirname("/usr/local/lib", 2);

Output:

/usr

This is equivalent to dirname(dirname("/usr/local/lib")), but reads more clearly when you need to climb several levels.

Edge cases to know

dirname() has a few results that surprise people the first time:

<?php

echo dirname("example.txt"), "\n";   // "."  — no directory part, so current dir
echo dirname("/"), "\n";             // "/"  — root has no parent
echo dirname(""), "\n";              // "."

• A path with no directory component returns . (the current directory), not an empty string.
• The root path returns itself.
• On Windows, both / and \ are accepted as directory separators.

dirname() vs. related functions

• basename() — the opposite of dirname(): it returns the last component (the file or folder name) instead of the parent directory.
• pathinfo() — returns an array with dirname, basename, extension, and filename all at once, which is handy when you need more than one piece.
• realpath() — resolves a path against the real filesystem (following symlinks and ..), unlike dirname(), which is text-only.

A common pattern is building paths relative to the current file:

<?php

// Load config that sits one directory above this script.
require dirname(__DIR__) . "/config.php";

Conclusion

dirname() extracts the parent directory from a path as a simple string operation. Remember that it never checks the filesystem, that a path with no directory returns ., and that the $levels argument lets you climb several directories in a single call. For the complementary file-name half of a path, reach for basename(); for everything at once, use pathinfo().

Practice