What are some best practices for specifying file paths when using fopen in PHP to avoid errors related to file access permissions?

When specifying file paths in PHP using fopen, it's important to use absolute paths rather than relative paths to avoid potential errors related to file access permissions. Absolute paths provide a clear and direct path to the file, ensuring that the script can locate and access it regardless of the current working directory. By using absolute paths, you can avoid issues with file permissions that may arise when using relative paths.

// Specify the absolute path to the file
$file_path = '/var/www/html/example.txt';

// Open the file using fopen with the absolute file path
$file_handle = fopen($file_path, 'r');

// Check if the file was opened successfully
if ($file_handle) {
    // File operations can be performed here
    fclose($file_handle);
} else {
    echo "Unable to open file.";
}