What are common issues when setting chmod permissions in PHP scripts?

Common issues when setting chmod permissions in PHP scripts include incorrect file paths, improper permission values, and insufficient file ownership. To solve these issues, ensure that the file paths are correct, use the appropriate permission values (e.g., 0644 for files and 0755 for directories), and make sure that the PHP script has the necessary permissions to modify the files.

// Set the correct file path and permission value
$file_path = '/path/to/file.txt';
$permission = 0644;

// Check if the file exists and set the permissions
if (file_exists($file_path)) {
    chmod($file_path, $permission);
    echo 'Permissions set successfully.';
} else {
    echo 'File does not exist.';
}