Refactored the persistent history to be reusable in other places.

.irbrc

@@ -4,19 +4,25 @@ require 'irb/completion'
require 'wirb'
Wirb.start
# Make irb's history persistent
irbhistory = File.join Dir.home, ".irbhistory"
last_history = File.read irbhistory rescue ""
last_history.lines.each do |line|
  Readline::HISTORY.push line.strip
end
def save_history
  puts "Writing history back..."
  File.write irbhistory, Readline::HISTORY.to_a.uniq.reduce { |x,y| "#{x}\n#{y}" }
# A history of commands separated by lines.
#  @param hist_file the path to the history file (like ~/.bash_history)
#  @param hist_src the 'backend' that records the history.
#                  Must respond to #to_a and #push.
class StoredHistory
  def initialize hist_file, hist_src=Readline::HISTORY
    @history = hist_file
    @src     = hist_src
    
    last_history = File.read @history rescue ""
    last_history.lines.each do |line|
      @src.push line.strip
    end
    
    at_exit do
      puts "Writing history back to #{@history}"
      File.write @history, @src.to_a.uniq.reduce { |x,y| "#{x}\n#{y}" }
    end
  end
end
at_exit do
  save_history
end
StoredHistory.new File.join(Dir.home, ".irbhistory")