With optical character recognition (OCR), you can scan the contents of a document into a single file of editable text. This article, which focuses on scanning books, describes the steps you need to take to prepare pages for optimal OCR results, and compares various free OCR tools to determine which is the best at extracting the text.

nmap is a wonderful tool specially for debugging, there are lots of times when you need to know if a port is open in a server, or maybe blocked by a firewall, or just to test your iptables rules. Here we will learn how to use it at the command line, and using its GUI front end, nmapFE and Knmap.