You'd need to hold HUGE index's and you'd never get results as good as other search engines. Unless you are doing this as more an educational thing, I wouldn't bother. I noticed wget (while reading its man page) has some basic crawling abilities, but I have now idea if it's any use. I've also seen spiderfetch (
http://cli-apps.org/content/show.php...?content=84905) which looked promising, but again I haven't actually tried it and so don't honestly know. Best of luck if you do go through with it!