We will assume for the rest of the book that you have an editor open, the newest Rust compiler ready, and a command line available. As of the time of writing, the newest version is 1.24.1. Because of Rust's strong guarantees about backward compatibility, you can rest assured that all of the recipes shown (with the exception of Chapter 10, Using Experimental Nightly Features) are always going to work the same way. You can download the newest compiler with its command-line tools at https://www.rustup.rs.