golang 执行系统命令 ps aux | grep "xxxx",总是异常退出

|exec.Command()

func Demo() (err error) {
    psCmd := exec.Command("ps", "aux")
    psStdout, psStderr := SetCommandStd(psCmd)
    err = psCmd.Run()
    if err != nil {
      err = errors.New(err.Error() + psStderr.String())
      return
    }
    // 筛选
    grepCmd := exec.Command("grep", "mysql")
    grepCmd.Stdin = psStdout
    grepStdout, grepStderr := SetCommandStd(grepCmd)
    err = grepCmd.Run()
    if err != nil {
      err = errors.New(err.Error() + grepStderr.String())
      return
    }
}

func SetCommandStd(cmd *exec.Cmd) (stdout, stderr *bytes.Buffer) {
    stdout = &bytes.Buffer{}
    stderr = &bytes.Buffer{}
    cmd.Stdout = stdout
    cmd.Stderr = stderr
    return
}