Getting stderr from exec.Cmd

package main

import (
        "bytes"
        "os/exec"
)

func main() {
    app := "/path/to/your/program"

    arg0 := "first"
    arg1 := "second here"

    cmd := exec.Command(app, arg0, arg1)
    var e bytes.Buffer
    cmd.Stderr = &e
    out, err := cmd.Output()

    if err != nil {
        println(err.Error())
        return
    }

    print(string(out))
    print(string(e.Bytes()))
}