The Exception in the thread "main" org. Apache. Hadoop. Mapred. FileAlreadyExistsException: the Output directory: L/crawl/index already exists! Can you tell me the problem how to solve? Twice I execute the command./nutch crawl urls - dir L: 1-1 - threads/crawl - the depth topN 10, will put the error, and the reason is the first execution has generated the index directory, don't I grab every time want to empty crawl directory? Please advice,