Rust 🦀 Installation + Hello World

Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.

In this article, we will see:

• how to install Rust on Linux, Mac, and Windows
• how to use rustc to compile a Rust program
• how to use cargo to compile and run a Rust program
• how to use cargo check to check if a Rust program compiles without producing an executable
• how to use cargo build --release to create a production-ready executable

If you prefer a video version

Rust installation

Rust can be installed by using the rustup tool. Rustup installs rustc, cargo, rustup and other standard command line tools.

Installing Rust on Linux and Mac

Open your terminal and run the following command:

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

This downloads and runs rustup-init.sh, which in turn downloads and runs the correct version of the rustup-init executable for your platform.

Installing Rust on Windows

Go to https://www.rust-lang.org/tools/install and download the installer.

You may need to install the Visual Studio C++ Build tools when prompted to do so.

You can also install Rust on a Windows Subsystem for Linux (WSL) distribution.

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

Verifying the installation

Open your terminal and run the following command:

rustc --version

Updating Rust

Before we start, a good practice is to update Rust to the latest version.

rustup update

Uninstalling Rust

Open your terminal and run the following command:

rustup self uninstall

Rust local documentation

Open your terminal and run the following command:

rustup doc

Rust playground

You can also try Rust online using the Rust playground: https://play.rust-lang.org/

We are now ready to start learning Rust.

Rust hello world

You can use any IDE you want to write Rust code, but I recommend using VSCode with the rust-analyzer and Even Better TOML extensions.

On an empty folder, open your terminal and run the following command:

touch main.rs

Open the main.rs file in your favorite editor and add the following code:

fn main() {
    println!("Hello world!");
}

Your project should look like this:

Rust is a compiled language, meaning your code is translated (compiled) to machine code that your computer can understand.

Open your terminal and run the following command:

rustc main.rs

This will create an executable' main' file in the same directory. Run the following command to execute the file:

./main

You should see the following output:

As we can see, Rust generated a file, which is the executable file that we can run.

Let's try something unusual: open the main.rs file and modify it as follows:

fn main(){
    println!("Hello, world!");
    //wait for 3 seconds
    std::thread::sleep(std::time::Duration::from_secs(3));
}

You can add comments in Rust by using // for single-line comments and /* */ for multi-line comments.

Now run the following commands:

rustc main.rs
./main

You should see the following output:

And let's try to run the executable file generated by double-clicking on it.

This is powerful. We can run the executable file generated by Rust on any computer without having to install Rust on that computer.

This was my first ah-ha moment with Rust.

Of course, this is not a functionality exclusive to Rust, but the fact that it is so embedded in the language is amazing.

Rust hello world using cargo

Cargo is Rust's build system and package manager.

Cargo handles tasks such as

• building your code
• downloading the libraries your code depends on
• building those libraries

It is similar to npm in Node.js or pip in Python.

You can check the version of cargo by running the following command:

cargo --version

Before proceeding, let's check https://crates.io/, the official Rust package registry.

Let's delete everything in this directory and create a new project using cargo:

cargo new hello_world
cd hello_world

Your project should look like this:

I love how simple the files generated by cargo are.

We have

• a Cargo.toml file, which is the manifest file for Rust projects. It contains information about the project, such as the name, version, dependencies, authors, and more.
• a src directory containing the project's source code, with a main.rs file inside.
• a .gitignore file contains the files and directories that git should ignore.

Note: the cargo new command creates a new folder, but if you want to create a new project in the current directory, you can run cargo init instead.

Cargo.toml

TOML stands for Tom's Obvious, Minimal Language. It is a simple configuration file format that is designed to be easy to read due to obvious semantics.

If you want to highlight TOML files in VSCode, you can install the Better TOML extension.

Now, it is a crucial part of understanding how Rust does work. Rust is a compiled language, meaning your code is translated (compiled) to machine code that your computer can understand.

Open your terminal and run the following command:

cargo build

This will create a target directory with a debug directory inside. Inside the debug directory, you will find an executable file called hello_world.

Run the following command to execute the file:

./target/debug/hello_world

And this should output Hello, world!.

Good, but we should not have to type ./target/debug/hello_world every time we want to run our program.

Open the file main.rs and make any modifications to the code, for example, instead of println!("Hello, world!"); write println!("Hello, cargo!");.

So let's run the following command:

cargo run

This will compile and run our program.

We can also use the rust-analyzer extension to run our program by clicking on the Run button.

We can also use cargo check to check if our code compiles without producing an executable.

cargo check

Let's try to produce an error on purpose. Open the main.rs file and rename the println! macro to pritln!.

Now run:

cargo check

You should see the following error:

As you can see, not only does cargo check check if the code compiles, but it also provides useful information about the error, suggesting that a similar macro exists.

Let's fix the error and run cargo check again:

Now the compiler is happy.

Cargo.lock

Before we end this, let's discuss the Cargo.lock file.

This file is automatically generated by cargo and should not be edited manually.

It contains information about the dependencies of the project, such as the version of the dependencies.

This file is used to ensure that the same version of the dependencies is used by everyone working on the project.

Building for release

When you are ready to release your project, you can run the following command:

cargo build --release

This will create an executable file in the target/release directory.

This executable will be optimized for release, meaning it will run faster than the executable created by cargo build.

We can run the executable by running the following command:

./target/release/hello_world

As we can see, it's on a different directory than the executable created by cargo build.

Conclusion

In this article, we learned

• how to install Rust on Linux, Mac, and Windows
• how to use rustc to compile a Rust program
• how to use cargo to compile and run a Rust program
• how to use cargo check to check if a Rust program compiles without producing an executable
• how to use cargo build --release to create a production-ready executable

If you prefer a video version

If you have any comments, leave them below.

To find Francesco, go here: https://francescociulla.com