Expand description
Command Line Argument Parser for Rust
Quick Links:
Aspirations
- Out of the box, users get a polished CLI experience
- Including common argument behavior, help generation, suggested fixes for users, colored output, shell completions, etc
- Flexible enough to port your existing CLI interface
- However, we won’t necessarily streamline support for each use case
- Reasonable parse performance
- Resilient maintainership, including
- Willing to break compatibility rather than batching up breaking changes in large releases
- Leverage feature flags to keep to one active branch
- Being under WG-CLI to increase the bus factor
- We follow semver and will wait about 6-9 months between major breaking changes
- We will support the last two minor Rust releases (MSRV, currently 1.56.1)
While these aspirations can be at odds with fast build times and low binary size, we will still strive to keep these reasonable for the flexibility you get. Check out the argparse-benchmarks for CLI parsers optimized for other use cases.
Example
Run
$ cargo add clap -F derive
(See also feature flag reference)
Then in main.rs
:
use clap::Parser;
/// Simple program to greet a person
#[derive(Parser, Debug)]
#[clap(author, version, about, long_about = None)]
struct Args {
/// Name of the person to greet
#[clap(short, long, value_parser)]
name: String,
/// Number of times to greet
#[clap(short, long, value_parser, default_value_t = 1)]
count: u8,
}
fn main() {
let args = Args::parse();
for _ in 0..args.count {
println!("Hello {}!", args.name)
}
}
Then try it out:
$ demo --help
clap [..]
A simple to use, efficient, and full-featured Command Line Argument Parser
USAGE:
demo[EXE] [OPTIONS] --name <NAME>
OPTIONS:
-c, --count <COUNT> Number of times to greet [default: 1]
-h, --help Print help information
-n, --name <NAME> Name of the person to greet
-V, --version Print version information
$ demo --name Me
Hello Me!
(version number and .exe
extension on windows replaced by placeholders)
See also the derive tutorial and reference
Related Projects
Augment clap:
- wild for supporting wildcards (
*
) on Windows like you do Linux - argfile for loading additional arguments from a file (aka response files)
- shadow-rs for generating
Command::long_version
- clap_mangen for generating man page source (roff)
- clap_complete for shell completion support
CLI Helpers
Testing
trycmd
: Bulk snapshot testingsnapbox
: Specialized snapshot testingassert_cmd
andassert_fs
: Customized testing
Documentation:
Re-exports
Modules
unstable-doc
Documentation: Cookbook
unstable-doc
Documentation: Derive Reference
unstable-doc
Documentation: FAQ
unstable-doc
Documentation: Feature Flags
unstable-doc
Documentation: Builder Tutorial
Error reporting
Macros
cargo
Deprecated, replaced with clap::command!
cargo
Allows you to build the Command
instance from your Cargo.toml at compile time.
cargo
Allows you to pull the authors for the command from your Cargo.toml at
compile time in the form:
"author1 lastname <author1@example.com>:author2 lastname <author2@example.com>"
cargo
Allows you to pull the description from your Cargo.toml at compile time.
cargo
Allows you to pull the name from your Cargo.toml at compile time.
cargo
Allows you to pull the version from your Cargo.toml at compile time as
MAJOR.MINOR.PATCH_PKGVERSION_PRE
Select a ValueParser
implementation from the intended type
Structs
The abstract representation of a command line argument. Used to set all the options and relationships that define a valid argument for the program.
Container for parse results.
Iterate over indices for where an argument appeared when parsing, via ArgMatches::indices_of
Deprecated, replaced with ArgMatches::get_many()
A possible value of an argument.
Deprecated, replaced with ArgMatches::get_many()
Enums
Application level settings, which affect how Command
operates
Behavior of arguments when they are encountered while parsing
Various settings that apply to arguments and may be set, unset, and checked via getter/setter
methods Arg::setting
, Arg::unset_setting
, and Arg::is_set
. This is what the
Arg
methods which accept a bool
use internally.
Represents the color preferences for program output
Command line argument parser kind of error
Contains either a regular expression or a set of them or a reference to one.
Provide shell with hint on how to complete an argument.
Origin of the argument’s value
Traits
Parse arguments into enums.
Parse a set of arguments into a user-defined container.
Create a Command
relevant for a user-defined container.
Converts an instance of ArgMatches
to a user-defined container.
Parse command-line arguments into Self
.
Parse a sub-command into a user-defined enum.
Parse arguments into enums.
Type Definitions
Build a command-line interface.