1. Getting Started

1.1 Install

rustup: a command line tool for managing Rust versions and associated tools.

$ curl --proto '=https' --tlsv1.2 https://sh.rustup.rs -sSf | sh

# A C compiler is required
# because some common Rust packages depend on C code and will need a C compiler.
# On macOS, you can get a C compiler by running:
xcode-select --install


$ rustup update


rustup self uninstall

Version check:

rustc --version

1.2 Write, Compile and Run

$ mkdir ~/projects
$ cd ~/projects
$ mkdir hello_world
$ cd hello_world
$ touch main.rs

Rust files always end with the .rs extension. If you’re using more than one word in your filename, use an underscore to separate them. For example, use hello_world.rs rather thanhelloworld.rs.

Now open the main.rs file you just created and enter the code in Listing 1-1.

Filename: main.rs

fn main() {
    println!("Hello, world!");
  • fn
  • println! calls a Rust macro. If it called a function instead, it would be entered as println (without the !)
  • semicolon

1.3 Cargo

Check cargo's version:

cargo --version

Create a project with cargo:

$ cargo new hello_cargo
$ cd hello_cargo

Build and run:

cargo build
cargo run

Cargo also provides a command called cargo check. This command quickly checks your code to make sure it compiles but doesn’t produce an executable:

cargo check

When your project is finally ready for release, you can use cargo build --release to compile it with optimizations.

This command will create an executable in target/release instead of target/debug. The optimizations make your Rust code run faster, but turning them on lengthens the time it takes for your program to compile. This is why there are two different profiles: one for development, when you want to rebuild quickly and often, and another for building the final program you’ll give to a user that won’t be rebuilt repeatedly and that will run as fast as possible. If you're benchmarking your code's running time, be sure to run cargo build --release and benchmark with the executable in target/release.