code: function get (url, cb) {
    var urls = [], end
    _get(url, cb)
    function _get (url) {
      urls.push(url)
      if(end) return
      if(urls.length > 5)
        cb(end = new Error('too many redirects\n'+JSON.stringify(urls)))
  
      console.error('GET', url)
      ;(/^https/.test(url) ? https : http).get(url, function next (res) {
  
        if(res.statusCode >= 300 && res.statusCode < 400)
          _get(res.headers.location)
        else {
          end = true,
          cb(null, res)
        }
      })
      .on('error', function (err) {
        if(!end)
          cb(end = err)
      })
    }
  }
docs: pull a package from the registry