I was made sad by the complexity of involving STDIN when using std::process module:

fn o_to_0() -> std::io::Result<bool> {
    let mut p = std::process::Command::new("tr")
        .arg("o") .arg("0") .stdin(std::process::Stdio::piped())
    let input = "foo"; if let Some(stdin) = p.stdin.as_mut() {
    stdin.write_all(input.as_bytes())?; } Ok(p.wait()?.success())

I wonder if this can be more easy, in other languages and/or libraries.

I made two submissions, and gave some commentary on another.