urfave-cli/docs/v2/getting-started.md

tags	search
v2	boost 2

One of the philosophies behind cli is that an API should be playful and full of discovery. So a cli app can be as little as one line of code in main().

package main

import (
	"os"

	"github.com/urfave/cli/v2"
)

func main() {
	(&cli.App{}).Run(os.Args)
}

This app will run and show help text, but is not very useful. Let's give an action to execute and some help documentation:

package main

import (
	"fmt"
	"log"
	"os"

	"github.com/urfave/cli/v2"
)

func main() {
	app := &cli.App{
		Name:  "boom",
		Usage: "make an explosive entrance",
		Action: func(*cli.Context) error {
			fmt.Println("boom! I say!")
			return nil
		},
	}

	if err := app.Run(os.Args); err != nil {
		log.Fatal(err)
	}
}

Running this already gives you a ton of functionality, plus support for things like subcommands and flags, which are covered below.