Working with the File System in PHP: A Complete Guide for Beginners

Introduction: Why Does PHP Need to Work with Files?

Any web project will sooner or later face the need to save data on the server. Whether it's uploading a user avatar, creating error logs, or generating reports — all of this requires the ability to manage files and folders. PHP provides a powerful set of functions for working with the file system, and mastering them is not as difficult as it seems.

In this article, we will cover the basic operations: creating, reading, writing, deleting files and directories, as well as checking access permissions. All examples are written in pure PHP and are ready to use in your projects.

1. Basics: Opening, Reading, and Writing Files

Before doing anything with a file, you need to open it. For this, PHP uses the fopen() function. It returns a resource (a file pointer) that you can then work with.

File Opening Modes

The second parameter of fopen() is the access mode. Here are the most popular ones:

• 'r' — read-only, pointer at the beginning of the file.
• 'w' — write (creates the file or truncates an existing one).
• 'a' — append to the end of the file (creates it if it doesn't exist).
• 'x' — create and write; if the file already exists, an error occurs.

Example: Writing Text to a File

<?php$filename = 'test.txt';$file = fopen($filename, 'w') or die('Could not open file');$text = "Hello, world!";fwrite($file, $text);fclose($file);echo 'File written successfully';?>

After writing, always close the file with the fclose() function — this frees up system resources.

Reading a File Line by Line

<?php$file = fopen('test.txt', 'r');while (!feof($file)) {    $line = fgets($file);    echo $line . '<br>';}fclose($file);?>

The feof() function checks if the end of the file has been reached. fgets() reads one line.

Simpler Alternatives

For quick operations, PHP offers wrapper functions:

• file_get_contents($filename) — reads the entire file into a string.
• file_put_contents($filename, $data) — writes a string to a file (creates or overwrites).

<?php// Reading$content = file_get_contents('test.txt');echo $content;

// Writingfile_put_contents('new.txt', 'Simple write');?>

2. Managing Directories: Creating, Deleting, Navigating

Working with folders in PHP is almost as simple as working with files. The main functions are mkdir(), rmdir(), and scandir().

Creating a Folder

<?php$dir = 'uploads';if (!is_dir($dir)) {    mkdir($dir, 0777, true);    echo 'Folder created';} else {    echo 'Folder already exists';}?>

The parameter 0777 is the access permissions (mask). The third argument true allows creating nested directories recursively (e.g., images/2024/).

Deleting a Folder

The rmdir() function only deletes an empty directory. If there are files inside, you need to clear it first:

<?phpfunction removeDir($dir) {    if (!is_dir($dir)) return;    $items = scandir($dir);    foreach ($items as $item) {        if ($item == '.' || $item == '..') continue;        $path = $dir . '/' . $item;        if (is_dir($path)) {            removeDir($path);        } else {            unlink($path);        }    }    rmdir($dir);}removeDir('temp');echo 'Folder deleted';?>

Getting a List of Files in a Folder

<?php$files = scandir('uploads');foreach ($files as $file) {    if ($file != '.' && $file != '..') {        echo $file . '<br>';    }}?>

3.