Go by Example: Hello World ref: http://qiita.com/giwa@github/items/02a3a0eb01800bda62ee

file0.txt

brew update
brew install go

file1.txt

export GOROOT=/usr/local/opt/go/libexec
export GOPATH=$HOME/go
export PATH=$GOPATH/bin:$GOROOT/bin:$PATH

file2.go

package main

import "fmt"

func main() {
    fmt.Println("hello world")
}

file3.txt

$ go run hello-world.go
hello world

$ go build hello-world.go
$ ls
hello-world hello-world.go

$./hello-world
hello world