index.js

var fs = require('fs');
var zlib = require('zlib');
var tar = require('tar');

var stream = fs.createReadStream('twbs-bootstrap-v3.2.0-0-gc068162.tar.gz').on('error', console.log);
stream.pipe(zlib.Unzip())
.pipe(tar.Parse())
.on('entry', function(e) {
  var path = e.props.path;
  if(/^.*\/docs/.test(path)) console.log(path);
});