fn main() {
    let search_term = "picture";

    let quote = "Every face, every shop, bedroom window, public-house, and dark square
    is a picture feverishly turned--in search of what?\
    It is the same with books. What do we seek through millions of pages?";

    for (idx, line) in quote.lines().enumerate() {
        if line.contains(search_term) {
            let line_num = idx + 1;
            println!("{}: {}", line_num, line)
        }
    }
}
