Building a CLI with Cobra

Cobra CLI Framework

This lesson explains the main concept clearly with beginner-friendly examples and background so you can learn why the code works.

Cobra powers kubectl, git, and many other tools.

package main

import (
    "fmt"
    "github.com/spf13/cobra"
)

var rootCmd = &cobra.Command{ Use: "app", Short: "Demo CLI" }

var helloCmd = &cobra.Command{
    Use:   "hello [name]",
    Short: "Print a greeting",
    Args:  cobra.ExactArgs(1),
    Run: func(cmd *cobra.Command, args []string) {
        fmt.Printf("Hello, %s!\n", args[0])
    },
}

func init() { rootCmd.AddCommand(helloCmd) }

func main() { rootCmd.Execute() }

Run it:

$ go run main.go hello World
Hello, World!

Persistent flags

rootCmd.PersistentFlags().BoolP("verbose", "v", false, "Enable verbose output")