Test the usage of the flag package in go's stdlib.

test_flag.go

package main

import (
    "os"
    "fmt"
    "flag"
)

func main() {
    help := flag.Bool("help", false, "Print help message")
    vsn  := flag.Bool("version", false, "Print version info")
    host := flag.String("host", "localhost", "Specify listening host")
    port := flag.Int("port", 8000, "Specify listening port")

    fmt.Println("flag.PrintDefaults: ")
    flag.PrintDefaults()
    fmt.Println()

    fmt.Println("os.Args: ", os.Args)
    fmt.Println()

    flag.Parse()

    fmt.Println("flag.Parse results: ")
    fmt.Println("  help: ", *help)
    fmt.Println("  vsn: ", *vsn)
    fmt.Println("  host: ", *host)
    fmt.Println("  port: ", *port)
    fmt.Println("  Args: ", flag.Args())
}