Usage

Usage is a spec, CLI, and Rust framework for defining command-line interfaces. Arguments, flags, environment variables, and config files can all be described in a portable KDL spec. Think of it as OpenAPI for CLIs: one declaration can drive parsing and every user-facing artifact.

• Generate shell completions
• Generate Markdown documentation and man pages
• Parse arguments from any language
• Scaffold a spec into CLI frameworks in different languages
• Build a typed Rust CLI with a zero-dependency runtime

See more at usage.jdx.dev.

Rust framework

Applications can use usage-rs to derive a typed parser and a portable Usage spec from the same Rust declaration:

[dependencies]
usage = { package = "usage-rs", version = "6" }

use usage::Cli;

#[derive(Cli)]
#[usage(bin = "example", version)]
struct App {
    /// Print more detail.
    #[usage(short = 'v', long, count)]
    verbose: u8,

    /// Files to process.
    files: Vec<String>,
}

fn main() {
    let app = App::parse();
    // app.verbose and app.files are ready to use
}

Usage has its own derive vocabulary: use #[usage(...)] on commands, fields, and value variants. See the Rust framework guide and clap migration guide for the supported mappings and intentional differences.

Sponsors

usage is sponsored by entire.io and 37signals.

View all sponsors.

Acknowledgements

Usage's design owes a great deal to clap. Its help output and diagnostic conventions make clap migrations familiar, while Usage's native derive attributes reflect its portable spec model. clap's license is reproduced in NOTICE.md.

License

MIT. Third-party notices are in NOTICE.md.