Environment Variables

Read and use environment variables.

Difficulty

Beginner

Code

use std::env;

fn main() {
    match env::var("HOME") {
        Ok(val) => println!("HOME: {}", val),
        Err(e) => println!("not set: {}", e),
    }

    let port = env::var("PORT").unwrap_or("8080".to_string());
    println!("PORT: {}", port);
}

Explanation

std::env::var reads environment variables.

Key Concepts

• Read the code carefully and understand the data flow
• Try modifying the example to see how it changes behavior
• Run this code in the Rust Playground

Related Topics

Browse more examples in the cli category to build a complete understanding of this topic.