[Go] Judging current system with switch

package main

import (
    "fmt"
    "runtime"
)

func main() {
    fmt.Print("Go runs on ")
    os := runtime.GOOS
    switch os {
    case "windows":
        fmt.Println("Windows")
    case "darwin":
        fmt.Println("Mac")
    case "linux":
        fmt.Println("GNU/Linux")
    default:
        // freebsd, openbsd, plan9...
        fmt.Printf("%s.", os)
    }
}