A Tour of Go Switch

package main 

import (
    "fmt"
    "runtime"
)

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