golang并发ping主机的方法

package main

import (
  "bufio"
  "bytes"
  "fmt"
  "io"
  "io/ioutil"
  "log"
  "os"
  "os/exec"
  "strings"
  "sync"
  "runtime"
)

func RunCMD(command string) string {
  in := bytes.NewBuffer(nil)
  cmd := exec.Command("sh")
  cmd.Stdin = in
  in.WriteString(command + "\n")
  stdout, err := cmd.StdoutPipe()
  if err != nil {
    log.Fatal(err)
  }
  defer stdout.Close()
  if err := cmd.Start(); err != nil {
    log.Fatal(err)
  }
  opBytes, err := ioutil.ReadAll(stdout)
  if err != nil {
    log.Fatal(err)
  }
  return string(opBytes)
}

func ping(ip string) string {
  cmd := "ping -fc 100 " + ip
  return RunCMD(cmd)
}

var ips = []string{}

func main() {
  runtime.GOMAXPROCS(runtime.NumCPU())
  fileName := "pinglist.txt"
  f, err := os.Open(fileName)
  if err != nil {
    fmt.Println(err)
  }
  buf := bufio.NewReader(f)
  for {
    line, err := buf.ReadString('\n')
    line = strings.TrimSpace(line)
    if err != nil {
      if err == io.EOF {
        //fmt.Println("File read over!")
        break
      }
      fmt.Println(err)
    }
    ips = append(ips, line)
  }
  wg := &sync.WaitGroup{}
  ch := make(chan string, len(ips))
  //fmt.Println(ips)
  for i:= 0; i