PHP File Handling: A Comprehensive Guide

Learn how to read, write, and manipulate files in PHP using practical examples and modern best practices.

📖 1. Outputting a File with `readfile()`

The readfile() function reads a file and writes it directly to the output buffer. It is useful when you just want to output the contents of a file directly to the browser without modifying it.

Example

<?php
// Reads and outputs the content of webdictionary.txt
echo readfile("webdictionary.txt");
?>

📂 2. Opening and Closing a File

For more control, use fopen() and fclose(). fopen() provides various modes such as r (read), w (write), and a (append). Always close files after you are done.

<?php
// Open a file for reading
$file = fopen("webdictionary.txt", "r") or die("Unable to open file!");

// Do some file operations...

// Always close the file to free up resources
fclose($file);
?>

🔍 3. Reading File Contents

Using fread(), you can read from an open file. You must pass the file pointer and the maximum length (in bytes) to read.

<?php
$file = fopen("webdictionary.txt", "r") or die("Unable to open file!");

// Read the complete file using filesize()
echo fread($file, filesize("webdictionary.txt"));

fclose($file);
?>

✍️ 4. Writing to a File

Using fwrite(), you can write data to a file. Be careful with mode w, as it will overwrite the file. Use mode a if you wish to append without deleting existing content.