Bagaimana untuk mendapatkan output daripada os.exec dalam go

cmdstring := "lxc exec " + containername + " -- ip addr show eth0 | grep 'inet\b' | awk '{print $2}' | cut -d/ -f1"
ip, err := exec.command("bash", "-c", cmdstring).output()
fmt.println(ip)

ip, err := exec.command("lxc", "exec ", containername, " --", "ip addr show eth0", "|", "grep", "'inet\b'", "| awk '{print $2}'", "| cut -d/", "-f1").output()
fmt.println(ip)

[root@localhost toolbox]# lxc exec simon -- ip addr show eth0 | grep 'inet\b' | awk '{print $2}' | cut -d/ -f1
10.183.201.38

package main

import (
    "bytes"
    "fmt"
    "os/exec"
)

func main() {
    cmd := exec.Command("/usr/bin/ls")
    buf := bytes.Buffer{}
    cmd.Stdout = &buf
    err := cmd.Run()

    fmt.Println(buf.String(), err)
}