diff --git a/judge/scripts/grader b/judge/scripts/grader
new file mode 100755
--- /dev/null
+++ b/judge/scripts/grader
@@ -0,0 +1,217 @@
+#!/usr/bin/ruby
+
+def stop_grader(id)
+  if id==:all
+    File.open(File.dirname(__FILE__) + "/stop.all",'w').close
+  else
+    File.open(File.dirname(__FILE__) + "/stop.#{id}",'w').close
+  end
+end
+
+def check_stopfile
+  FileTest.exist?(File.dirname(__FILE__) + "/stop.all") or
+    FileTest.exist?(File.dirname(__FILE__) + "/stop.#{Process.pid}")
+end
+
+def clear_stopfile
+  if FileTest.exist?(File.dirname(__FILE__) + "/stop.#{Process.pid}")
+    system("rm " + File.dirname(__FILE__) + "/stop.#{Process.pid}")
+  end
+end
+
+def config
+  Grader::Configuration.get_instance
+end
+
+def log_file_name
+  if !File.exists?(config.log_dir)
+    raise "Log directory does not exist: #{config.log_dir}"
+  end
+  config.log_dir + 
+    "/#{GRADER_ENV}_#{config.grader_mode}.#{Process.pid}"
+end
+
+def log(str)
+  if config.talkative
+    puts str
+  end
+  if config.logging
+    fp = File.open(log_file_name,"a")
+    fp.puts("GRADER: #{Time.new.strftime("%H:%M")} #{str}")
+    fp.close
+  end
+end
+
+def display_manual
+  puts <<USAGE
+Grader.
+using: (1) grader 
+       (2) grader environment [mode]
+       (3) grader stop [all|pids-list]
+       (4) grader --help
+(1) call grader with environment = 'exam', mode = 'queue'
+(2) possible modes are: 'queue', 'prob', 'test_request'
+(3) create stop-file to stop running grader in queue mode
+(4) You are here.
+USAGE
+end
+
+#########################################
+# main program
+#########################################
+
+# with --help
+if (ARGV.length==1) and (/help/.match(ARGV[0]))
+  display_manual
+  exit(0)
+end
+
+# reading environment and options
+if (ARGV.length >= 1) and (ARGV[0]=='stop')
+  if ARGV.length==1
+    puts "you should specify pid-list or 'all'"
+    display_manual
+  elsif (ARGV.length==2) and (ARGV[1]=='all')
+    stop_grader(:all)
+    puts "A global stop file ('stop.all') created."
+    puts "You should remove it manually later."
+  else
+    (1..ARGV.length-1).each do |i|
+      stop_grader(ARGV[i])
+    end
+    puts "stop file(s) created"
+  end
+  exit(0)
+end
+
+if check_stopfile
+  puts "Stop file exists.  Terminated."
+  clear_stopfile
+  exit(0)
+end
+
+grader_mode = 'queue'
+if ARGV.length >= 1
+  GRADER_ENV = ARGV[0]
+  if ARGV.length >=2
+    grader_mode = ARGV[1]
+  end
+else
+  GRADER_ENV = 'exam'
+end
+
+puts "environment: #{GRADER_ENV}"
+require File.join(File.dirname(__FILE__),'config/environment')
+
+# add grader_mode to config
+# this is needed because method log needs it.  TODO: clean this up
+class << config
+  attr_accessor :grader_mode
+end
+config.grader_mode = grader_mode
+
+# reading rails environment
+log 'Reading rails environment'
+
+RAILS_ENV = config.rails_env
+require RAILS_ROOT + '/config/environment'
+
+# register grader process
+if config.report_grader
+  grader_proc = GraderProcess.register(config.grader_hostname,
+                                       Process.pid,
+                                       grader_mode)
+else
+  grader_proc = nil
+end
+
+#set loggin environment
+ENV['GRADER_LOGGING'] = log_file_name
+
+# register exit handler to report inactive, and terminated
+at_exit do
+  if grader_proc!=nil
+    grader_proc.report_inactive 
+    grader_proc.terminate
+  end
+end
+
+#
+# MAIN LOOP
+#
+
+case grader_mode
+when "queue", "test_request"
+  log "Grader: #{grader_mode}"
+  if grader_mode=="queue"
+    engine = Grader::Engine.new
+  else
+    engine = Grader::Engine.new(Grader::TestRequestRoomMaker.new,
+                                Grader::TestRequestReporter.new)
+  end
+
+  runner = Grader::Runner.new(engine, grader_proc)
+  while true
+    
+    if check_stopfile    # created by calling grader stop
+      clear_stopfile
+      log "stopped (with stop file)"
+      break
+    end
+    
+    if grader_mode=="queue"
+      task = runner.grade_oldest_task
+    else
+      task = runner.grade_oldest_test_request
+    end
+    if task==nil
+      sleep(1)
+    end
+  end
+  
+when "prob"
+  engine = Grader::Engine.new
+  runner = Grader::Runner.new(engine, grader_proc)
+
+  grader_proc.report_active if grader_proc!=nil
+
+  ARGV.shift
+  ARGV.shift
+
+  ARGV.each do |prob_name|
+    prob = Problem.find_by_name(prob_name)
+    if prob==nil
+      puts "cannot find problem: #{prob_name}"
+    else
+      runner.grade_problem(prob)
+    end
+  end
+
+when "sub"
+  engine = Grader::Engine.new
+  runner = Grader::Runner.new(engine, grader_proc)
+
+  grader_proc.report_active if grader_proc!=nil
+
+  ARGV.shift
+  ARGV.shift
+
+  ARGV.each do |sub_id|
+    puts "Grading #{sub_id}"
+    begin
+      submission = Submission.find(sub_id.to_i)
+    rescue ActiveRecord::RecordNotFound
+      puts "Record not found"
+      submission = nil
+    end
+
+    if submission!=nil
+      runner.grade_submission(submission)
+    end
+  end
+
+else
+  display_manual
+  exit(0)
+end
+