Rust Echo Command Implementation
I would not say I am any more proficient but I would make these changes if I wrote it.


skip(1) first arg.
join(" ") instead of iterate though args. 


You do not need a mutable value. 

use std::env;

fn main() {
    let args: Vec&lt;String&gt; = env::args().skip(1).collect();

    if args.len() == 0 {
        println!("");
    } else {
        println!("{}", args.join(" "));
    }
}


I would do one more thing and send to stdout since your mimicking echo, but maybe much for this answer.