sub.js

const request = require('request')
const fs = require('graceful-fs')

fs.readFile('data.txt', 'utf-8', (err, res) => {
  var data = res.replace(/<BR>/g, '\n').split('\n').map(val => (val.substr(0, 1) != '.') ? val : val.substr(1, val.length - 1)).slice(0, -1)

  function go(count) {
    var link = 'http://' + data[count]

    request(link, {forever: false, timeout: 15000}, function(err, response, body) {

      if (!err) {
        console.log(response.statusCode + ': ' + link)
        if (response.statusCode == 200) {
          fs.appendFileSync('ok.txt', link + '\n')
        }
      } else {
        console.log('err: ' + err.code + '|' + link)
      }

      if (count < data.length) {
        go(count + 1)
      } else {
        console.log('finished: ' + Date())
      }

    })
  }

  console.log('started: ' + Date())
  go(0)

})