Getting Started with Rust: Hello World & Cargo

Welcome to the first post of my Rust journey!
This article walks you through setting up Rust, writing your first program, and understanding Cargo — Rust’s package manager and build tool.

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📦 What You'll Learn

• Installing Rust on Linux, macOS, and Windows

• Writing your first Rust program: Hello, world!

• Introduction to Cargo: Rust’s package manager

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🔧 Installing Rust

Rust is installed using rustup, a command-line tool for managing Rust versions and associated tools.

▶️ Linux & macOS:

curl https://sh.rustup.rs -sSf | sh

To use Rust immediately without restarting your terminal:

source $HOME/.cargo/env

If needed, add Rust to your path manually:

export PATH="$HOME/.cargo/bin:$PATH"

Make sure a C linker is installed — often comes with a C compiler like gcc.

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🪟 Windows:

1. Go to rust-lang.org/install

2. Install Rust and the C++ build tools for Visual Studio
   (recommended: Build Tools for VS 2017)

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✅ Verify Installation

rustc --version

You should see something like:

rustc 1.XX.X (commit_hash YYYY-MM-DD)

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👋 Writing Your First Rust Program

1. Create a Project Directory

Linux/macOS:

mkdir ~/projects && cd ~/projects
mkdir hello_world && cd hello_world

Windows PowerShell:

mkdir $env:USERPROFILE\projects\hello_world
cd $env:USERPROFILE\projects\hello_world

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2. Create the Source File

Create a file named main.rs:

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

3. Compile and Run

Linux/macOS:

rustc main.rs
./main

Windows CMD:

rustc main.rs
.\main.exe

You should see:

Hello, world!

Congratulations, you're a Rustacean now 🦀!

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🧠 Understanding the Code

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

• fn main() defines the entry point.

• println! is a macro (notice the !) that prints text to the terminal.

• Every line ends with ; to mark the end of the statement.

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When you build or compile your Rust project, it generates some important files. Let’s break them down:

📄 main.rs

This is your main Rust source file — where your program starts.
It usually looks like this:

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

📁 For projects created with Cargo, this file is found at:

src/main.rs

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⚙️ main.exe (on Windows)

This is the compiled executable file. It's created when you build your project using:

rustc main.rs
# OR
cargo build

On Windows, the output is:

main.exe

You can run it directly:

./main.exe

On Linux/macOS, it will simply be named main instead of main.exe.

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🧠 main.pdb

This is a debug info file (PDB = Program Database). It's only created on Windows and contains:

• Line numbers

• Function names

• Variable info

It helps debuggers like gdb, lldb, or Visual Studio Debugger map your executable back to the original Rust code.

🛠️ It’s generated by default when you build in debug mode:

cargo build

📦 Introducing Cargo

Cargo is Rust’s official tool for:

• Creating new projects

• Building code

• Managing dependencies

• Publishing packages

Cargo comes pre-installed with Rust (via rustup).

🔍 Check Cargo:

cargo --version

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🏗️ Creating a New Project with Cargo

cargo new hello_cargo --bin
cd hello_cargo

This creates:

hello_cargo/
├── Cargo.toml
└── src/
    └── main.rs

The Cargo.toml file defines metadata and dependencies.
src/main.rs is where your code goes.

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🏃 Build & Run the Project

cargo build      # Compile
cargo run        # Compile & run
cargo check      # Quickly check for compile errors (no binary output)

Use cargo run when testing and cargo check while coding frequently.

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⚡ Build for Release

cargo build --release

This compiles with optimizations for production and outputs to target/release.