History and autocompletion in irb

If you missing bash-like history in irb you should just add following lines to ~/.irbrc

require 'irb/ext/save-history'
IRB.conf[:SAVE_HISTORY] = 100
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-history"

And this one for autocompletion:

require 'irb/completion'