## The Magic of Regular Expressions Regular Expressions (Regex) are query strings designed for finding, matching, and editing text. While highly powerful, the dense syntax can be intimidating. ### Common Regex Flags - `g` (Global): Find all matches rather than stopping at the first. - `i` (Case Insensitive): Ignore letter capitalization. - `m` (Multiline): Treat start/end anchors (`^` and `$`) as working across lines. ### Best Practices for Regex Design Always test your expressions against multiple pass and fail test-cases. An incorrect regex can cause severe performance issues (like catastrophic backtracking) or block valid user inputs. Use our visual **Regex Tester** to safely build patterns.