Hello Cargo

In truth, we rarely call the Rust compiler directly like that. Rust comes with a package manager called cargo which does all kinds of things for us, including calling rustc.

In fact, cargo will write the "hello world" program! If we use "cargo new" to create a new project

$ cargo new hello
     Created binary (application) `hello` package

Then we get a directory called "hello" with a few things already in it

$ tree hello
hello
├── Cargo.toml
└── src
    └── main.rs

1 directory, 2 files

If we look in that src/main.rs file, we see the "hello world" program

$ cat hello/src/main.rs 
fn main() {
    println!("Hello, world!");
}

If we change to that directory, then "cargo run" will first call the compiler and then run the resulting executable

$ cd hello
$ cargo run
   Compiling hello v0.1.0 (/home/tim/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.28s
     Running `target/debug/hello`
Hello, world!

So this is more like a typical workflow in Rust. Not bad, right? Cargo really takes the rough edges off. It does a whole lot more too, so we'll be seeing it again.