gistfile1.txt

HISTFILE = "~/.irb_history"
MAXHISTSIZE = 100

begin
  if defined? Readline::HISTORY
    histfile = File::expand_path( HISTFILE )
    if File::exists?( histfile )
      lines = IO::readlines( histfile ).collect {|line| line.chomp}
      puts "Read %d saved history commands from %s." %
        [ lines.nitems, histfile ] if $DEBUG || $VERBOSE
      Readline::HISTORY.push( *lines )
    else
      puts "History file '%s' was empty or non-existant." %
        histfile if $DEBUG || $VERBOSE
    end

    Kernel::at_exit {
      lines = Readline::HISTORY.to_a.reverse.uniq.reverse
      lines = lines[ -MAXHISTSIZE, MAXHISTSIZE ] if lines.nitems > MAXHISTSIZE
      $stderr.puts "Saving %d history lines to %s." %
        [ lines.length, histfile ] if $VERBOSE || $DEBUG
      File::open( histfile, File::WRONLY|File::CREAT|File::TRUNC ) {|ofh|
	lines.each {|line| ofh.puts line }
      }
    }
  end
end