Pry is an interactive shell for the Ruby programming language. It is notable for its Smalltalk-inspired ability to start a REPL within a running program. This lets programmers debug and modify the current state of a system.
Pry project is hosted from pryrepl.org 
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There are good arguments for running pry over irb. Ruby people (rubles?) summarize this as "pry blew my mind".
# Installing `gem install pry pry-doc`
# Recommendations
* pry-byebug - use Pry with byebug.
* pry-rails - use Pry for rails console (`rails c`)
# Tricks
If you're in a project and have some common stuff you want to load into your repl environment, well pry supports rc files! Here's an awesome one to start you off:
files = Dir["lib/*.rb"] if files.size > 0 puts "autoloading..." files.each do |file| puts " require_relative #{file}" require_relative file end end