ri

Doc Rdoc ..

https://www.omniref.com/ruby/gems/httparty/0.13.1/symbols/HTTParty::ClassMethods/default_params

http://ruby-doc.org/stdlib-2.0.0/libdoc/minitest/rdoc/MiniTest/Assertions.html#method-i-assert_equal

http://www.rubydoc.info/gems/minitest/5.8.3/Minitest/Assertions#assert_equal-instance_method

ri Array#each

If you have still this in ~/.gemrc file (still works)

gem: --no-ri --no-rdoc

Change it into

# ~/.gemrc
install: --no-document
update: --no-document
gem: --no-document

because we have this new flag, and the old --no-ri flag has been deprecated.

-​-[no-]document [TYPES] - Generate documentation for installed gems List the documentation types you wish to generate. For example: rdoc,ri

However if you have it this way, you can have ri command for all gems with you.

--document ri
--no-document rdoc

http://ruby-doc.org/
http://www.rubydoc.info/

To update, I found ri command useful http://www.jstorimer.com/blogs/workingwithcode/7766081-5-reasons-you-should-use-ri-to-read-ruby-documentation

all std-lib or core-ruby are already there. And for any gem, you can always download ri documentation to you then remove it. use gem rdoc

gem rdoc minitest --ri
ri Minitest::Assertions.assert_equal
gem rdoc httparty --no-ri --overwrite

or when you install

$ gem install httparty --document ri
$ ri default_params