Regex, short for “regular expression,” is a small pattern that helps a computer find or check matching text. For example, a pattern can look for words that contain only numbers or check whether a line includes a date in a familiar format.
Think of it like a search rule: instead of looking for one exact phrase, you describe the kind of text you want. Regex can save time when handling lots of text, but complicated patterns can be hard to read. For common jobs such as working with web addresses, a built-in tool may be clearer and safer.