gistfile1.rb

# Module for re-running commands from the history in irb and its ilk (script/console)
# Usage:
#   history => view the history
#   history 7 => rerun line 7 in the history
#   history /foo/ => rerun the last line in the history matching /foo/
#
# Just add this code into your ~/.irbrc.
# NOTE: Readline support is required for this to work.
module HistoryRepeats
  class << self
    def history(repeat=nil)
      case repeat
      when Integer
        re_run {Readline::HISTORY[repeat]}
      when Regexp
        re_run {Readline::HISTORY.to_a.reverse.detect{|l| l =~ repeat}}
      when nil
        Readline::HISTORY.each_with_index do |line, i|
          puts "#{i} #{line}"
        end
        nil
      end
    end

    private
    def re_run
      # Remove the history command from the history
      Readline::HISTORY.pop

      command = yield

      # Let the user know what we're executing
      puts command

      # Put the new command into the history...
      Readline::HISTORY.push(command)

      # ...and execute it in IRB's CurrentContext
      IRB.CurrentContext.evaluate(command, IRB.CurrentContext.instance_eval('@line_no'))
    end
  end
end

def history(*args)
  HistoryRepeats.history(*args)
end