Hello World in Rust

Our first program will print the classic “hello world” message. Here’s the full source code.

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

To run the program, put the code in hello_world.rs and use cargo run.

$ cargo new hello_world --bin
$ cd hello_world
$ cargo run
hello world

Sometimes we’ll want to build our programs into binaries. We can do this using cargo build --release, which creates an optimized binary.

$ cargo build --release
$ ls target/release/
hello_world

We can then execute the built binary directly.

$ ./target/release/hello_world
hello world

Now that we can run and build basic Rust programs, let’s learn more about the language.