1use clap::{arg, command, value_parser};
2
3fn main() {
4 let matches = command!() // requires `cargo` feature
5 .arg(
6 arg!([PORT])
7 .value_parser(value_parser!(u16))
8 .default_value("2020"),
9 )
10 .get_matches();
11
12 println!(
13 "port: {:?}",
14 matches
15 .get_one::<u16>("PORT")
16 .expect("default ensures there is always a value")
17 );
18}
19