Ruby 2.5.9 Standard Library Documentation


Welcome to the Ruby Standard Library Documentation collection, brought to you by Ruby-doc. Whether you are browsing online or offline, we hope that your use of Ruby's standard library will become more productive as a result of this effort.

Ruby-doc is a project dedicated to creating and collecting documentation on Ruby.

stdlib-doc is a RubyForge project that converts Ruby source code into this documentation you are looking at.

What You'll Find Here

Each package in the Ruby standard library (found in lib/ directory of the Ruby source code, or lib/ruby/1.x/ of a Ruby installation) has been run through RDoc and the results have been collected here.

ruby-doc volunteers and library authors add comments to the Ruby source code repository, and it is those comments that RDoc captures for display in this collection. As there are many libraries and few volunteers, this is a long task.


Much of the documentation itself has been created by Gavin Sinclair, William Webber, Lyle Johnson, James Edward Gray II, and library authors. Individual library files usually have code and documentation credits. was created and is maintained by James Britt/Neurogami.

Gavin Sinclair wrote the software (ruby stdlib-doc.rb gendoc --all) to generate this webpage (thanks, Amrita!).

James Britt did some later hacking to bring some things up to date and to have it play nice with different Ruby versions.

Thanks to Dave Thomas for RDoc, without which this project would be impossible.