#![allow(unused)]
use std::io::{BufRead, BufReader};
use std::process;

fn main() {
    let mut child = process::Command::new("yes")
        .stdout(process::Stdio::piped())
        .spawn()
        .expect("Failed to exec");

    // ここでstdoutを何行かprintして
    let buf = BufReader::new(child.stdout.as_mut().unwrap());
    buf.lines().take(10).for_each(|l| {println!("{:?}", l.unwrap())});

    // killしたい
    child.kill().unwrap();
}