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Clikt (pronounced “clicked”) is a multiplatform Kotlin library that makes writing command line interfaces simple and intuitive. It’s the “Command Line Interface for Kotlin”.

It is designed to make the process of writing command line tools effortless while supporting a wide variety of use cases and allowing advanced customization when needed.

Clikt has:

  • arbitrary nesting of commands
  • composable, type safe parameter values
  • support for a wide variety of command line interface styles
  • multiplatform packages for JVM, NodeJS, and native Linux, Windows and MacOS

What does it look like? Here’s a complete example of a simple Clikt program:

class Hello : CliktCommand() {
    val count: Int by option(help="Number of greetings").int().default(1)
    val name: String by option(help="The person to greet").prompt("Your name")

    override fun run() {
        repeat(count) {
            echo("Hello $name!")
        }
    }
}

fun main(args: Array<String>) = Hello().main(args)

And here’s what it looks like when run:

 $ ./hello --count=3
 Your name: John
 Hello John!
 Hello John!
 Hello John!

The help page is generated for you:

$ ./hello --help
Usage: hello [OPTIONS]

Options:
  --count INT  Number of greetings
  --name TEXT  The person to greet
  -h, --help   Show this message and exit

Errors are also taken care of:

$ ./hello --whoops
Usage: hello [OPTIONS]

Error: no such option: "--whoops".

Installation

Clikt is distributed through Maven Central.

dependencies {
   implementation("com.github.ajalt.clikt:clikt:3.2.0")
}
In version 3.0, the maven coordinates changed. Make sure you’re using the new coordinates if you’re updating from an older version.
If you’re using Maven instead of Gradle, use <artifactId>clikt-jvm</artifactId>

Multiplatform

Clikt supports the following targets: jvm, mingwX64, linuxX64, macosX64, and js (for both NodeJS and Browsers). See the docs for more information about functionality supported on each target. You’ll need to use Gradle 6 or newer.

Snapshots

Snapshot builds are also available

You'll need to add the Sonatype snapshots repository:

repositories {
    maven {
        url = uri("https://oss.sonatype.org/content/repositories/snapshots/")
    }
}

API Reference