use std::process::Command;

let output = Command::new("echo")
                     .arg("Hello world")
                     .output()
                     .expect("Failed to execute command");

assert_eq!(b"Hello world\n", output.stdout.as_slice());

use std::process::{Command, Stdio};

// stdout must be configured with `Stdio::piped` in order to use
// `echo_child.stdout`
let echo_child = Command::new("echo")
    .arg("Oh no, a tpyo!")
    .stdout(Stdio::piped())
    .spawn()
    .expect("Failed to start echo process");

// Note that `echo_child` is moved here, but we won't be needing
// `echo_child` anymore
let echo_out = echo_child.stdout.expect("Failed to open echo stdout");

let mut sed_child = Command::new("sed")
    .arg("s/tpyo/typo/")
    .stdin(Stdio::from(echo_out))
    .stdout(Stdio::piped())
    .spawn()
    .expect("Failed to start sed process");

let output = sed_child.wait_with_output().expect("Failed to wait on sed");
assert_eq!(b"Oh no, a typo!\n", output.stdout.as_slice());

use std::process::{Command, Stdio};
use std::io::Write;

let mut child = Command::new("/bin/cat")
    .stdin(Stdio::piped())
    .stdout(Stdio::piped())
    .spawn()
    .expect("failed to execute child");

{
    // limited borrow of stdin
    let stdin = child.stdin.as_mut().expect("failed to get stdin");
    stdin.write_all(b"test").expect("failed to write to stdin");
}

let output = child
    .wait_with_output()
    .expect("failed to wait on child");

assert_eq!(b"test", output.stdout.as_slice());