Introduction: Why Creating and Writing Files in PHP Matters

Creating and writing files is a fundamental task in PHP web development. Whether you're storing form data, logging user activity, generating reports, or saving configuration settings, file writing gives you a flexible way to store persistent data.

PHP offers multiple ways to create and write to files, ranging from low-level control using fopen() and fwrite() to simpler methods like file_put_contents().

In this tutorial, you'll learn the right way to create and write files in PHP, with code examples, best practices, and a working demo.

Methods to Create and Write Files in PHP

There are two main ways to write files in PHP:

1. Using fopen() and fwrite() – more control and options

2. Using file_put_contents() – simpler and quicker method

✍️ 1. Creating and Writing Files with fopen() and fwrite()

Step-by-Step

Step 1: Use fopen() with Write Mode

$file = fopen("example.txt", "w"); // "w" = write mode (creates or truncates file)

• "w" mode will create the file if it doesn't exist.

• It will overwrite existing content if the file already exists.

Step 2: Write to the File with fwrite()

fwrite($file, "This is the first line.\n");
fwrite($file, "This is the second line.\n");

Step 3: Close the File

fclose($file);

Closing is crucial to release the file handle and avoid memory leaks.

⚡ 2. Simpler Way: Using file_put_contents()

file_put_contents("example.txt", "This is some text.\n");

✅ Pros:

• Very concise

• Automatically creates the file

• Overwrites by default

Appending to a File

To append instead of overwrite:

file_put_contents("example.txt", "This line is added.\n", FILE_APPEND);

File Mode Options for fopen()

✅ Complete Working Example

<?php
$filename = "log.txt";
$data = "User logged in at " . date("Y-m-d H:i:s") . "\n";

// Option 1: Using fopen + fwrite
$file = fopen($filename, "a"); // Append mode
fwrite($file, $data);
fclose($file);

// Option 2: Using file_put_contents
file_put_contents($filename, $data, FILE_APPEND);

echo "Data successfully written to $filename";
?>

This script logs each access time into a file named log.txt.

Tips & Common Pitfalls

✅ Best Practices

• Use file_put_contents() for small, one-shot writes.

• Use fopen() for large or frequent writes (e.g., in loops).

• Always check permissions (file must be writable).

• Sanitize user input before writing to avoid file injection risks.

❌ Common Mistakes

• Overwriting important files by using "w" instead of "a".

• Forgetting to close file handles with fclose().

• Not checking if fopen() or fwrite() return false on failure.

• Using file_put_contents() on large files (inefficient).

Comparison Table: fwrite() vs. file_put_contents()

Conclusion: Writing Files in PHP – What You Should Remember

• PHP provides simple yet powerful tools for writing to files.

• Use fopen() and fwrite() when you need control and efficiency.

• Use file_put_contents() for quick and simple file writing.

• Always be cautious of overwriting data and ensure proper file permissions.

By mastering these functions, you unlock the ability to store logs, generate reports, export data, or even build file-based CMS features—all from scratch in PHP.