<DIV><p>Regular expressions remain a difficult part of the puzzle when learning how to program. Commonly used for sifting through large chunks of text, regexes are incredibly powerful although they may appear daunting to the newcomer. And variations among languages and environments make them even harder to master.</p><p> Loaded with examples, this introductory guide walks beginners step-by-step through the fundamentals of regular expressions, and helps you decipher complex patterns.</p><ul><li>Break down regular expressions into comprehensible parts </li><li>Learn common usage patterns through simple, easy-to-follow examples </li><li>Discover how finding unique patterns can help you avoid repetitive, hand-editing of text </li><li>Use common command-line tools such as grep and sed </li><li>Compare how regular expressions are implemented in different languages and environments </li></ul></div>