title: Crawl/scrape websites/webpages containing a specific text, with no prior information about any such websites/webpages
body: <p>I used nutch and scrapy.  They need seed URLs to crawl.  That means, one should be already aware of the websites/webpages which would contain the text that is being searched for.</p>
  
  <p>My case is different, I do not have the prior information about the websites/webpages which contain the text I am searching for.  So I won't be able to use seed URLs to be crawled by tools such as nutch and scrapy.</p>
  
  <p>Is there a way to crawl websites/webpages for a given text, without knowing any websites/webpages that would possibly contain that text?</p>