四大机器人的代码

upring

Googlebot/2.1+(+http://www.google.com/bot.html)
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google

Baiduspider+(+http://www.baidu.com/search/spider.htm)

% _) s; w3 R" w. ~7 Z/ xbaidu
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+Yahoo!+Slurp;+http://help.yahoo.com/help/us/ysearch/slurp
yahoo
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