What is the recommended directory separator to use in PHP for cross-platform compatibility?

When working with file paths in PHP, it's important to use the DIRECTORY_SEPARATOR constant to ensure cross-platform compatibility. This constant will automatically use the correct directory separator based on the operating system (e.g., "/" for Unix-based systems and "\" for Windows). By using DIRECTORY_SEPARATOR, your code will work seamlessly on different platforms without the need for manual adjustments.

$filePath = 'path' . DIRECTORY_SEPARATOR . 'to' . DIRECTORY_SEPARATOR . 'file.txt';