What are the differences between absolute paths, relative paths, and base paths in PHP, and when should each be used?

Absolute paths in PHP start with a forward slash (/) and represent the full path from the root directory of the server. Relative paths are specified relative to the current working directory of the script. Base paths are used to define a common starting point for relative paths. Absolute paths should be used when referencing files or directories that are located outside of the current working directory. Relative paths are suitable for referencing files or directories within the same directory structure. Base paths can be used to simplify the referencing of files or directories by providing a common starting point for relative paths.

// Absolute path example
$absolutePath = '/var/www/html/myproject/file.txt';

// Relative path example
$relativePath = 'images/photo.jpg';

// Base path example
$basePath = '/var/www/html/myproject/';

// Using absolute path
$fileContent = file_get_contents($absolutePath);

// Using relative path with base path
$fileContent = file_get_contents($basePath . $relativePath);