GNU Screen is a terminal multiplexer that allows users to manage multiple terminal sessions from a single window. It enables users to create, detach, and reattach to sessions, making it easier to run long processes without needing to keep the terminal open. This is particularly useful for remote work, as users can disconnect and reconnect without losing their progress. With GNU Screen, users can also share sessions with others, facilitating collaboration. It supports multiple windows within a single session, allowing users to switch between different tasks seamlessly. Overall, it enhances productivity and flexibility in command-line environments.