A simple addition to access Mac OS X's pbcopy & pbpaste commands from IRB.

irbrc.rb

module Clipboard
  def pbcopy(data)
    IO.popen('pbcopy', 'w') {|io| io.write(data)}
  end

  def pbpaste
    IO.popen('pbpaste', 'r').read
  end
end

include Clipboard

usage

>> pbcopy "Test"
=> 4
>> pbpaste
=> "Test"