// Note: this requires the `cargo` feature fn main() { let app = clap::App::new("cargo") .bin_name("cargo") .subcommand_required(true) .subcommand( clap::app_from_crate!().name("example").arg( clap::arg!(--"manifest-path" ) .required(false) .allow_invalid_utf8(true), ), ); let matches = app.get_matches(); let matches = match matches.subcommand() { Some(("example", matches)) => matches, _ => unreachable!("clap should ensure we don't get here"), }; let manifest_path = matches .value_of_os("manifest-path") .map(std::path::PathBuf::from); println!("{:?}", manifest_path); }