The [[Screen Tutorial|GNU [http://www.gnu.org/software/screen/ screen]] utility permits you to start a session, disconnect from it (accidentally or intentionally), and then reconnect from the same or another network connection. This is useful when you're using an unstable WiFi connection (e.g., in a coffee shop or mobile link) or want to start a long operation (such as a build or a test suite run) on campus, commute home while it's running, and then check on its status.