I have used a desktop application : RegExpBuddy for years. That is where I test my expressions and learn to understand what happens when for example choose greedy or not. It gives the reg expression in actual code for many different languages like javascript, php, powershell etc . It has helped me immensely. Its like a pocket calculator for regular expressions. Can also recommend the Mastering Regular Expression book mention by Rowley . I once took a pluralsight course that took the subject seriously; not just quick fix recipes.