Start a new project in Go

1. mkdir hello_world
2. go mod init example.com/hello_world to init a Go module in the cwd
3. Create a go file with a package main and a func main()

package main
 
import "fmt"
 
func main() {
	fmt.Println("Hello, world!")
}

4. go build to create an executable with the module name that can be run with ./hello_world
5. or go run .