PHP filetype Function

last modified April 3, 2025

The PHP filetype function determines the type of a file or directory. It returns a string indicating the type of the specified file.

Basic Definition

The filetype function returns the type of the given file. Possible return values include 'file', 'dir', 'link', and other system-specific types.

Syntax: filetype(string $filename): string|false. The function returns false on failure. It requires the file to exist and be accessible.

Basic filetype Example

This shows the simplest usage of filetype to check a file type.

basic_filetype.php

<?php

declare(strict_types=1);

$filename = "example.txt";
$type = filetype($filename);

echo $type; // Outputs: file (if example.txt exists)

This checks the type of "example.txt". The function returns 'file' for regular files. Make sure the file exists before checking its type.

Checking Directory Type

filetype can distinguish between files and directories.

directory_type.php

<?php

declare(strict_types=1);

$dirname = "docs";
$type = filetype($dirname);

echo $type; // Outputs: dir (if docs is a directory)

Here we check if "docs" is a directory. The function returns 'dir' for directories. The same path rules apply as with files.

Checking Symbolic Link

The function can identify symbolic links on systems that support them.

symlink_type.php

<?php

declare(strict_types=1);

$linkname = "shortcut.lnk";
$type = filetype($linkname);

echo $type; // Outputs: link (if it's a symlink)

This checks if "shortcut.lnk" is a symbolic link. The function returns 'link' for symlinks. Note behavior may vary by operating system.

Handling Non-Existent Files

filetype returns false and generates a warning for missing files.

nonexistent_file.php

<?php

declare(strict_types=1);

$filename = "missing.txt";
$type = filetype($filename);

if ($type === false) {
    echo "File not found or inaccessible";
}

This demonstrates proper error handling. Always check the return value when the file might not exist. Consider using file_exists first.

Checking Special File Types

On Unix systems, filetype can identify special file types.

special_types.php

<?php

declare(strict_types=1);

$fifo = "/path/to/named.pipe";
$type = filetype($fifo);

echo $type; // Outputs: fifo (if it's a named pipe)

This checks for a FIFO (named pipe) file type. Other possible values include 'char' for character devices and 'block' for block devices on Unix systems.

Best Practices

Error Handling: Always check for false return values.
File Existence: Verify files exist before checking type.
Permissions: Ensure proper read permissions for target.
Caching: Be aware of stat cache in repeated calls.
Cross-platform: Some types are OS-specific.

Source

PHP filetype Documentation

This tutorial covered the PHP filetype function with practical examples showing its usage for different file types and 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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