IRB stands for "interactive Ruby" and is a tool to interactively execute Ruby expressions read from the standard input.
irb command from your shell will start the interpreter.
Add this line to your application's Gemfile:
And then execute:
Or install it yourself as:
$ gem install irb
Use of irb is easy if you know Ruby.
When executing irb, prompts are displayed as follows. Then, enter the Ruby expression. An input is executed when it is syntactically complete.
$ irb irb(main):001:0> 1+2 #=> 3 irb(main):002:0> class Foo irb(main):003:1> def foo irb(main):004:2> print 1 irb(main):005:2> end irb(main):006:1> end #=> nil
The Readline extension module can be used with irb. Use of Readline is default if it's installed.
The following commands are available on IRB. You can get the same output from the
IRB cwws Show the current workspace. chws Change the current workspace to an object. workspaces Show workspaces. pushws Push an object to the workspace stack. popws Pop a workspace from the workspace stack. irb_load Load a Ruby file. irb_require Require a Ruby file. source Loads a given file in the current session. irb Start a child IRB. jobs List of current sessions. fg Switches to the session of the given number. kill Kills the session with the given number. irb_info Show information about IRB. show_cmds List all available commands and their description. Debugging debug Start the debugger of debug.gem. break Start the debugger of debug.gem and run its `break` command. catch Start the debugger of debug.gem and run its `catch` command. next Start the debugger of debug.gem and run its `next` command. delete Start the debugger of debug.gem and run its `delete` command. step Start the debugger of debug.gem and run its `step` command. continue Start the debugger of debug.gem and run its `continue` command. finish Start the debugger of debug.gem and run its `finish` command. backtrace Start the debugger of debug.gem and run its `backtrace` command. info Start the debugger of debug.gem and run its `info` command. Misc edit Open a file with the editor command defined with `ENV["EDITOR"]`. measure `measure` enables the mode to measure processing time. `measure :off` disables it. Context show_doc Enter the mode to look up RI documents. ls Show methods, constants, and variables. `-g [query]` or `-G [query]` allows you to filter out the output. show_source Show the source code of a given method or constant. whereami Show the source code around binding.irb again.
NO_COLOR: Assigning a value to it disables IRB's colorization.
IRB_USE_AUTOCOMPLETE: Setting it to
falsedisables IRB's autocompletion.
EDITOR: Its value would be used to open files by the
IRBRC: The file specified would be evaluated as IRB's rc-file.
After checking out the repo, run
bin/setup to install dependencies. Then, run
rake test to run the tests. You can also run
bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run
bundle exec rake install. To release a new version, update the version number in
version.rb, and then run
bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the
.gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/irb.
rake release gh release create vX.Y.Z --generate-notes
The gem is available as open source under the terms of the 2-Clause BSD License.