clap – Fast. Configurable. Argument Parsing for Rust

About

clap or Command Line Argument Parser

Is a simple-to-use, efficient, and fully-configurable library for parsing command line arguments.

clap supports advanced features like argument relationships, subcommands, and much, much more.

A Quick Taste

The following Rust code is all it takes to get started:

extern crate clap; 
use clap::App; 

fn main() { 
    App::new("myapp")
       .version("1.0")
       .about("Does great things!")
       .author("Kevin K.")
       .get_matches(); 
}

extern crate clap;

use clap::App;

fn main() {

App::new("myapp")

.version("1.0")

.about("Does great things!")

.author("Kevin K.")

.get_matches();

}

If the user runs $ myapp --help the following would be printed

$ myapp --help
myapp 1.0 
Kevin K. 
Does great things! 

USAGE: 
    myapp [FLAGS] 

FLAGS: 
    -h, --help Prints this message 
    -V, --version Prints version information

$ myapp --help

myapp 1.0

Kevin K.

Does great things!

USAGE:

myapp [FLAGS]

FLAGS:

-h, --help Prints this message

-V, --version Prints version information

Features

Just a few of the many, many features

Fast

clap aims to be extremely fast and efficient. Arguments will be parsed without wasting CPU cycles or...

Configurable

clap is fully configurable, yet still has common defaults for those applications that simply want be...

Standards Based

clap supports all standard argument types, flags/switches, options, free/positional arguments, and e...

Effortless Auto Completion

clap can generate bash, fish, zsh and even PowerShell completion files at compile time! These can th...

Spend time building your application

Let us worry about the arguments

Why Choose clap

A few more features

Automatic Help

clap generates your help message and usage strings for you automatically from the list of valid argu...

User Suggestions

If the end user has a typo, clap will gently suggest a correction based on the current context. I...

Friendly Errors

clap generates friendly, and informative error messages. These messages kindly inform the end user o...

Intuitive

clap is extremely easy and intuitive to use. In fact, it’s so intuitive that all you may need is

Relationships

One can define argument relationships easily, and intuitively. This includes everything from require...

YAML Support

You can define your list of valid arguments in a YAML file, keeping your main.rs clean and tidy.

Meet the Team

Growing one step at a time

Kevin K.

Owner

OUR FACTS

Some Numbers that Speak

crates.io downloads

github stars

Dependant Repositories

amazing contributors

Latest blogs

Check out the latest posts from our blog

clap v3 Update – No More Strings

March 8, 2019

This is the second post in a series detailing the issues, progress, and design decisions used in clap v3. This post details removing the "stringly typed" natur...

clap v3 Update – Structopt