clap::Arg でオプションの指定なしでダイレクトに値を渡す方法 `clap` ### `clap` $ scanner -i 120.0.0.1 $ scanner 120.0.0.1 clap::Arg * `clap::arg` ### `std::env::arg``clap`

`long` `short` clap



use clap::{App, Arg};

let a = App::new("scanner").arg(
Arg::with_name("addr")
.help("the address to scan")
.required(true),
).get_matches();

let addr = a.value_of("addr").unwrap();


clap
<