naive_tail.rs

use std::io;
use std::io::prelude::*;
use std::io::BufReader;
use std::fs::File;

fn tail() -> io::Result<String>  {
    BufReader::new(File::open("/tmp/foo.txt")?).lines().last().unwrap_or(Ok(String::new()))
}

fn main() {
    match tail() {
        Ok(line) => println!("{}", line),
        Err(e) => println!("! {:?}", e.kind())
    }
}