Go で変数引数を使用してシステムコマンドを安全に実行するにはどうすればよいですか?

import (
    "fmt"
    "os/exec"
    "strings"
    "sync"
)

func exeCmd(cmd string, wg *sync.WaitGroup) {
    fmt.Println("command is ", cmd)
    // Splitting head (e.g., "g++") from the rest of the command (e.g., "-c file.cpp")
    parts := strings.Fields(cmd)
    head := parts[0]
    parts = parts[1:len(parts)]

    out, err := exec.Command(head, parts...).Output()
    if err != nil {
        fmt.Printf("%s", err)
    }
    fmt.Printf("%s", out)
    wg.Done() // Signal to waitgroup that this goroutine is done
}

func main() {
    wg := new(sync.WaitGroup)
    wg.Add(3)

    x := []string{
        "echo newline >> foo.o",
        "echo newline >> f1.o",
        "echo newline >> f2.o"}

    go exeCmd(x[0], wg)
    go exeCmd(x[1], wg)
    go exeCmd(x[2], wg)

    wg.Wait()
}