The interactive shell provides a command-line interface to Sage. When you are done using Sage, remember to type quit or exit at the Sage prompt, or press Ctrl-D, to exit the interactive shell. In the following examples, lines which start with the Sage command prompt sage: indicate commands that you need to type in. Lines without the prompt indicate output from Sage. Although most of the examples in this book utilize the notebook interface, they will work in the interactive shell, unless noted otherwise.