Hello World in Go

hello.go

package main

import (
    "os"
    "fmt"
    "flag"
    "path/filepath"
)

const version = "0.1.0"

func main() {

    var ver bool
    flag.BoolVar(&ver, "version", false, "display version number and exit")
    flag.BoolVar(&ver, "v", false, "display version number and exit")
    flag.Parse()

    // show version and exit
    if ver {
        fmt.Println(filepath.Base(os.Args[0]), "version", version)
        os.Exit(0)
    }
    
    
    fmt.Println("Hello World!")
}