File Basics

Write a file

file_put_contents is a quick way to save text.

<?php
$path = __DIR__ . "/notes.txt";
file_put_contents($path, "Hello from PHP\n");

Read a file

Confirm the file exists before reading.

if (is_file($path)) {
  echo file_get_contents($path);
}

Append lines

Use flags when you want to add without wiping prior content.

file_put_contents($path, "Another line\n", FILE_APPEND);

File safety

• Never let users choose arbitrary paths unchecked
• Prefer paths under your project directory
• Check return values and handle failure
• For large files, use streams instead of loading everything