This is an introductory lesson adapted from the Library Carpentry workshop on Introduction to working with Data that introduces people with library- and information-related roles, or those in the Humanities and Social Sciences professions that work with data, to using regular expressions. Regular expressions are a concept and an implementation used in many different programming environments for sophisticated pattern matching. They are an incredibly powerful tool that can amplify your capacity to find, manage, and transform data and files. The lesson provides background on the regular expression language and how it can be used to match and extract text and to clean data. No previous experience with programming is required.