extern crate clap; use clap::{App, Arg}; fn main() { let matches = App::new("My Super Program") .version("1.0") .author("Able ") .about("Does awesome things") .arg( Arg::with_name("file") .short("f") .long("file") .value_name("FILE") .help("Sets a custom config file") .takes_value(true), ) .get_matches(); match matches.value_of("file") { Some(file_path) => { println!("{}", file_path); // Start parsing that file } None => { println!("hi"); //start the prompt } } }