rust 命令行参数

clap = "2.32.0" 添加到Cargo.toml 文件里面
main.rs 代码如下

use clap::{App, Arg};

fn main() {
    let matches = App::new("command name ")
        .version("0.1.0")
        .author("<zyxjh21@126.com>")
        .about("Rust Command")
        .arg(
            Arg::with_name("file")
                .long("file")
                .help("Input file")
                .takes_value(true)
                .required(true))
        .arg(
            Arg::with_name("num")
                .long("num")
                .help("Input date")
                .takes_value(true)
                .required(true)
        )
        .get_matches();

    let myfile = matches.value_of("file").expect(" read input.txt error");
    let num_str:i32 = matches.value_of("num")
                        .expect(" error in read number")
                        .parse()
                        .expect(" error in transport ");
    println!("The file passed is: {}", myfile);
    println!("The number is: {}", num_str);
}