How to parse command line arguments with clap

Use the clap crate to define arguments declaratively and parse them automatically. Add clap to Cargo.toml, define a struct with #[derive(Parser)], and call parse() in main.

use clap::Parser;

#[derive(Parser, Debug)]
#[command(name = "myapp")]
struct Args {
    /// The query string to search for
    query: String,
    /// The path to the file to search in
    file_path: String,
}

fn main() {
    let args = Args::parse();
    println!("Searching for {} in {}", args.query, args.file_path);
}

Add this to Cargo.toml:

[dependencies]
clap = { version = "4", features = ["derive"] }

Clap is a tool that automatically handles command-line arguments for your Rust program so you don't have to write manual parsing code. You define what inputs your program expects, and Clap handles the rest, including generating help text and error messages. Think of it as a form validator for your terminal commands.