为什么我在scrapy shell中没有看到hxs和xxs

如题，其中一个可能的原因是使用的scrapy版本问题：

在0.16下：

参考：http://doc.scrapy.org/en/0.16/intro/tutorial.html

scrapy shell http://www.dmoz.org/Computers/Programming/Languages/Python/Books/

[ ... Scrapy log here ... ]

[s] Available Scrapy objects:
[s] 2010-08-19 21:45:59-0300 [default] INFO: Spider closed (finished)
[s]   hxs        
[s]   item       Item()
[s]   request    
[s]   response   <200 http://www.dmoz.org/Computers/Programming/Languages/Python/Books/>
[s]   spider     
[s]   xxs        
[s] Useful shortcuts:
[s]   shelp()           Print this help
[s]   fetch(req_or_url) Fetch a new request or URL and update shell objects
[s]   view(response)    View response in a browser

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而在0.24版本下：

参考：http://doc.scrapy.org/en/0.24/intro/tutorial.html

#记住：总是加上双引号，否则参数可能不工作
scrapy shell "http://www.dmoz.org/Computers/Programming/Languages/Python/Books/"

[ ... Scrapy log here ... ]

2014-01-23 17:11:42-0400 [default] DEBUG: Crawled (200)  (referer: None)
[s] Available Scrapy objects:
[s]   crawler    
[s]   item       {}
[s]   request    
[s]   response   <200 http://www.dmoz.org/Computers/Programming/Languages/Python/Books/>
[s]   settings   
[s]   spider     
[s] Useful shortcuts:
[s]   shelp()           Shell help (print this help)
[s]   fetch(req_or_url) Fetch request (or URL) and update local objects
[s]   view(response)    View response in a browser

In [1]: