There is a classic bit of computer wisdom that states “If you’ve got a problem, and decide to solve it with regular expressions, now you’ve got two problems.” This of course stems from the perception that regular expressions are a complicated mix of magic characters and Voodoo. Regular expressions can allow you to achieve elegant and concise program logic quickly and easily, but only once you’ve learned to understand how they work and why. Just about any Linux or Mac system comes with a powerful regex tool call grep and learning grep is an essential task for any power user or system administrator. Today, we’ll explore some of what you can do with grep and how it can be one of the most powerful tools in your geek arsenal.