PHP Reading and Writing Files

11/22/2025
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PHP file reading and writing example for beginners

PHP Reading and Writing Files

PHP Reading and Writing Files: A Complete Beginner-Friendly Guide

Working with files is an essential part of PHP development. Whether you’re building a logging system, uploading files, exporting reports, or storing user data, PHP provides powerful built-in functions to read, write, append, and manage files easily.

In this tutorial, you’ll learn:

  • How PHP interacts with files

  • How to read files using different methods

  • How to write and append data to files

  • Real-world developer examples

  • Important file-handling functions

  • Common best practices

Why File Handling Is Important in PHP?

File handling is used for:

  • Storing logs (log.txt)

  • Exporting data (report.txt, CSV files)

  • Reading configuration files

  • Saving form submissions

  • Reading templates

  • Processing uploaded files

PHP makes file handling simple with clear functions.

1. Reading Files in PHP

There are multiple ways to read a file. Here are the most commonly used methods.

Method 1: readfile() – Quick Output

Reads and outputs the file content directly to the browser.

readfile("data.txt");

Useful for small files.

Method 2: file_get_contents() – Read Entire File into a String

$content = file_get_contents("data.txt");
echo $content;

Best when you need file contents stored in a variable.

Method 3: file() – Read File Into an Array Line-by-Line

$lines = file("data.txt");
foreach ($lines as $line) {
    echo $line . "<br>";
}

Great for processing line-based data.

Method 4: fopen() with fread() – Manual File Reading

$handle = fopen("data.txt", "r");
$content = fread($handle, filesize("data.txt"));
fclose($handle);

echo $content;

More control over file reading.

2. Writing Files in PHP

You can create new files or write to existing ones.

Method 1: file_put_contents() – Easiest Way

$data = "Hello, this is a new message!";
file_put_contents("output.txt", $data);

This creates the file if it does not exist.

Append Data Instead of Overwriting

file_put_contents("output.txt", "\nNew Line Added", FILE_APPEND);

Method 2: fwrite() Using fopen()

$handle = fopen("output.txt", "w"); // w = write
fwrite($handle, "Writing using fwrite() function.");
fclose($handle);

Modes like w, a, r+, w+ provide flexibility.

File Modes in fopen()

Mode Description
r Read only
w Write (truncate file)
a Append
r+ Read & write
w+ Read & write (truncate file)
a+ Read & append

3. Checking If File Exists

if (file_exists("data.txt")) {
    echo "File found!";
} else {
    echo "File does not exist.";
}

4. Deleting a File

if (file_exists("old.txt")) {
    unlink("old.txt");
}

5. Real-World Example: Saving Form Data to a File

$name = $_POST['name'];
$email = $_POST['email'];

$entry = "Name: $name | Email: $email\n";
file_put_contents("submissions.txt", $entry, FILE_APPEND);

echo "Data saved successfully!";

This is commonly used in feedback forms.

6. Reading JSON File

$jsonData = file_get_contents("data.json");
$data = json_decode($jsonData, true);

print_r($data);

7. Writing JSON File

$data = ["name" => "Shubham", "role" => "Developer"];
file_put_contents("data.json", json_encode($data));

Best Practices for PHP File Handling

  • Always check if a file exists before reading

  • Close file handles after fopen()

  • Use file permissions wisely

  • Sanitize user input when writing to files

  • Avoid handling extremely large files without buffering

Conclusion

PHP provides a powerful set of functions to read, write, append, and manage files easily. Whether you're logging data, processing uploaded files, or exporting reports, mastering PHP file handling is an essential skill for backend development.

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