package main

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

func Cmd(cmd string) {
    fmt.Println("command is ", cmd)
    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.Println("out")
    fmt.Println(string(out))
}

func main() {
    Cmd(`echo "hello world" | /usr/bin/pbcopy`)
}

command is  echo "hello world" | /usr/bin/pbcopy
out
"hello world" | /usr/bin/pbcopy