getting-started.md

tags	search
v3	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"
	"context"

	"github.com/urfave/cli/v3"
)

func main() {
	(&cli.Command{}).Run(context.Background(), os.Args)
}

This app will run and show help text, but is not very useful.

$ wl-paste > hello.go
$ go build hello.go
$ ./hello
NAME:
   hello - A new cli application

USAGE:
   hello [global options] [command [command options]] [arguments...]

COMMANDS:
   help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --help, -h  show help (default: false)

Let's add an action to execute and some help documentation:

package main

import (
	"fmt"
	"log"
	"os"
	"context"

	"github.com/urfave/cli/v3"
)

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

	if err := cmd.Run(context.Background(), 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.