rgxg is described as 'command-line tool (and a C-library) that generates (extended) regular expressions' and is an app in the OS & Utilities category. There are eight alternatives to rgxg for a variety of platforms, including Windows, Android, iPhone, Android Tablet and iPad. The best alternative is RegexBuddy. It's not free, so if you're looking for a free alternative, you could try Multi String Search or Multi String Replacer. Other great apps like rgxg are Regex Lab .NET (Free, Open Source), RegEx Lab (Free), Expressions (Paid) and Regexenator (Free).
Multi String Replacer is a small and portable application that can be used to replace multiple strings at once. Its main functionality is String Swapping in which can be easily and quickly done. String swapping consists on replacing WordX with WordY and WordY with WordX.
Regex Lab .NET is a full-featured application for editing regular expressions. The application features a modern, highly functional UI allowing increased productivity when writing or debugging regular expression patterns.
RegEx Lab allows you to test regular expressions. The app highlights and underlines text to show matches and capture groups. There's also a handy cheatsheet and a results list view. It has a replace feature too.
Expressions is a minimal, distraction-free tool for experimenting with regular expressions. FEATURES - Minimalistic, non–distractive user interface. - Dark and light themes and full-screen mode. - Pattern syntax highlighting. - Pattern and text group highlighting.
Regexenator is a powerful yet simple regular expression tool for Android phones and tablets. You can use Regexenator to create, test, and evaluate regular expressions and search text for matches of your regular expressions.