import (
  "os"
  "exec"
  "fmt"
  "io"
)

func SendEmail() {
  argv := []string {"sendmail","-t"}

  cmd, err := exec.LookPath(argv[0])
  if err != nil {
    fatal("exec %s: %s", argv[0], err)
  }
  r,w,err := os.Pipe()
  if err !=nil {
    fatal("%v",err)
  }
  pid, err := os.ForkExec(cmd,argv,os.Environ(), "", []*os.File{r, os.Stdout, os.Stderr})
  if err != nil {
    fatal("%s", err)
  }
  input,err := os.Open("myEmail.txt", os.O_RDONLY, 0666)
  _, err = io.Copy(w, input)
  if err != nil {
    fatal("%v",err)
  }
  w.Close()
  os.Wait(pid, 0)
}

// Control de errores
func fatal(msg string, args ...interface{}) {
    fmt.Fprintf(os.Stderr, msg+"\n", args)
    os.Exit(2)
}