go pflag

go pflag

package main

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

var (
    help = pflag.BoolP("help", "h", false, "Show this help message.")
)

func main() {
    pflag.Parse()
    if *help {
        pflag.Usage()
        return
    }
    fmt.Println(123)
}