This is a screen capture of IRB improved by Reline.
Reline is compatible with the API of Ruby's stdlib 'readline', GNU Readline and Editline by pure Ruby implementation.
The gem is available as open source under the terms of the Ruby License.
Acknowledgments for rb-readline
In developing Reline, we have used some of the rb-readline implementation, so this library includes copyright notice, list of conditions and the disclaimer under the 3-Clause BSD License. Reline would never have been developed without rb-readline. Thank you for the tremendous accomplishments.