// +build ignore package main import ( "flag" "io/ioutil" "log" "os" ) var flOutput = flag.String("o", "", "output file to write") func main() { flag.Parse() err := ioutil.WriteFile(*flOutput, []byte(source), os.FileMode(0644)) if err != nil { log.Fatal(err) } } var source = ` package main import "fmt" func foo() { fmt.Println("brrnnt") } `