Regular expressions might seem arcane, but if you do any kind of software, they are a powerful hacker tool. Obviously, if you are writing software or using tools like grep, awk, sed, Perl, or just about any programming language, regular expressions can simplify many tasks. Even if you don’t need them directly, regular expression searches can help you analyze source code, search through net lists, or even analyze data captured from sensors.
If you’ve been using regular expressions for a long time, they aren’t very hard. But learning them for the first time can be tedious. Unless you try your hand at regular expression crosswords. The clues are regular expressions and the rows and columns all have to match the corresponding regular expressions.