Lesson 1.2 · 6 min

Make and run a project

Chatterbox needs a home: a folder with your code in it and a tool that builds and runs it. In Rust that tool is called cargo, and you will use it hundreds of times. Today you use it three times.

Adds to ChatterboxThe Chatterbox project exists and runs.

Install once

To follow along on your own machine, install Rust from rustup.rs. It installs the compiler and cargo. You can also stay in the page: every code box in this course runs in your browser. But Chatterbox is a real project, so you will want it on your computer by chapter 3, lesson 5 (a preview: that is the first lesson that needs a real terminal).

Make the project

Open a terminal and ask cargo for a new project called chatterbox:

Make a project

$ cargo new chatterbox
    Creating binary (application) `chatterbox` package
$ cd chatterbox

$ ls
Cargo.toml
src

Cargo made a folder with two things that matter. Cargo.toml is the project's name tag and settings. src/main.rs is where your code lives. Let us look at both.

The settings file

$ cat Cargo.toml
[package]
name = "chatterbox"
version = "0.1.0"
edition = "2024"

[dependencies]

You can ignore most of this for now. name and version do what they say. [dependencies] is an empty shelf where, in chapter 8, you will list the other people's code Chatterbox uses.

And here is the program cargo wrote for you in src/main.rs. It is the same shape as lesson 1.1:

src/main.rs, as cargo wrote it

fn main() {

println!("Hello, world!");

}

$ cargo run
Hello, world!

Run it

cargo run does both jobs from the last lesson: it compiles your code, then runs the result.

Build and run

$ cargo run
   Compiling chatterbox v0.1.0 (~/chatterbox)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.21s
     Running `target/debug/chatterbox`
Hello, world!

Chatterbox exists

That is it. You now have a project called Chatterbox that compiles and runs. It only says "Hello, world!" so far. In the next lesson you change what it says, and learn what makes println! so flexible.

Self-check

Say it out loud, then reveal

Self-checkRetrieval beats re-reading

Which command creates a new project?Reveal

cargo new chatterbox.

What is the difference between cargo run and cargo check?Reveal

cargo run compiles and then runs the program. cargo check only checks that the code makes sense, so it is faster.

Where does your code live?Reveal

In src/main.rs. Cargo.toml holds the project settings.

That is lesson 1.2. Tick it off so the course remembers where you are.

Next: 1.3 Printing and comments →

Sources Install Rust (rustup) · The Cargo Book: creating a new package