The Ruby Regex Debugger. Put your regex in the top pane, and your match text in the bottom pane. Kang will highlight the match text that matches and show you any match groups you have created down the right hand side.

Poor man's debugger heavily inspired by PySnooper

ruined is Ruby Source Level Debugger for educational purpose.

A set of convenience utils and debuggers for Ruby.

Uses Pry (http://rdoc.info/github/banister/pry/master/file/README.markdown) as a debugger and introspection tool.

Remote Debugging for Phusion Passenger

Nikita App is a developer tool that runs on Rubinius.

make debugger work more often

JdiHook is a ruby-scriptable Java debugger based on and around Sun's Java Debugging Interface (JDI) API.

Scriptable debugger written in Ruby for OSX, Wind32 and Linux

An extremely early build for a Ruby Debugging tool, designed to be able to hook into various classes and track changes. Not intended to be used by others at this stage.

A simple gem that quickly removes debugger breakpoints from code

Pry with useful gems included and some debugger shortcuts

ruby-debug is a fast implementation of the standard Ruby debugger debug.rb. It is implemented by utilizing a new Ruby C API hook. The core component provides support that front-ends can build on. It provides breakpoint handling, bindings for stack frames among other things.

Quick Ruby debugger. Easily print any object or string to the console and to your logs while you're working.

Linecache is a module for reading and caching lines. This may be useful for example in a debugger where the same lines are shown many times.