Task

Show how to get one of your process's environment variables.

The available variables vary by system;   some of the common ones available on Unix include:

   PATH
   HOME
   USER


use std::env;
 
fn main() {
    println!("{:?}", env::var("HOME"));
    println!();
    for (k, v) in env::vars().filter(|(k, _)| k.starts_with('P')) {
        println!("{}: {}", k, v);
    }
}
 