Building a Simple CLI Tool – Argument Parsing

Argument Parsing with flag

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

import "flag"

func main() {
    name := flag.String("name", "world", "name to greet")
    repeat := flag.Int("n", 1, "how many times to greet")
    flag.Parse()
    for i := 0; i < *repeat; i++ {
        fmt.Printf("Hello, %s!\n", *name)
    }
}

Run:

$ go run greet.go -name=Bob -n=3
Hello, Bob!
Hello, Bob!
Hello, Bob!

Sub‑commands with Cobra (see lesson‑23)