IRB is designed as a REPL.

Pry is desinged as a...

..REPL..

..debugger..

and packs a whole lot of other useful stuff.

Features

• Plugins

• Context switching

• Buffer editing

• Documentation display

• Medium for shell commands

• Gem interaction

• Friendly aliases

Plugins

pry-byebug: debugger

pry-theme: colorizes Pry

pry-doc: provides documentation

pry-globs: documents global variables

pry-rails: replaces IRB in Rails console

Context switching 

ls - shows which methods, constants and variables are in the current context.

• -m - show public methods defined on the object

• -p - show public, protected and private methods

• -g - show global variables + pry-globs

cd            - move into new context

reset         - reset the REPL to a clear state

whereami  - describe the current location

nesting      - show context nesting information

disable-pry - return from debugging mode

Buffer editing

show-input - show the contents of the input buffer for the current multi-line expression

amend-line - edit buffer content in a multi-line mode

edit - open a text editor. If FILE is not given it will edit buffer content. When a method/class/module is given, the code will open in text editor

Documentation display

show-doc / ri - show documentation for a method or a class

show-source - show the source of a method, class or a module

stat - show detailed method information

Medium for shell commands

cat - show part or a whole source file

prefix '.' - commands prefixed with a dot will be passed to the underlying shell

Gem interaction

gem-cd - move working directory into a gem's directory

gem-install - install and reload the gem cache

gem-list - list all gems

gem-open - open gem's directory in text editor

Aliases

!!! - exit program

$ - show source

? - show documentation

@ - whereami

show-method - show-source

Pry in Rails

• pry-rails: in addition to initializing console with Pry, it provides show-routes and show-model(s) commands

• pry-byebug: enables thorough debugging with step, next and continue commands. Easily dig into internals of Rails.

• find-method: recursively search for a method within a Class/Module or the current namespace

Less known niceties

• ; - will supress the output of the evaluation

• _ - will run the last evaluation

• use Pry's help command! It includes plugin descriptions as well

• customize your Pry experience in .pryrc

Resources

Pry website

The Gist