I'm looking for a good open source web crawler and i found these: DataparkSearch, GNU Wget, GRUB, Heritrix, ht://Dig, HTTrack, ICDL, mnoGoSearch, Nutch, Open Search Server, PHP-Crawler, tkWWW Robot, ...
I have some problem, when I try to write robots.txt for my site ... I find some issues by search on Google, and tell me about honor and not honoring robots.txt, how I can prevent it, can I perform it ...
Are there any free standalone crawlers that I can use apart from Google webmaster to analyze errors? Something that shows me all 404's, errors etc