Run 2to3

Some stuff is broken now.

41 files changed, 241 insertions, 240 deletions

diff --git a/kpov_judge/add_task.py b/kpov_judge/add_task.py
index 6bb3a2c..ce6713b 100755
--- a/kpov_judge/add_task.py
+++ b/kpov_judge/add_task.py
@@ -12,16 +12,16 @@ import glob
 import os
 
 def task_check(results, params):
-    data = urllib.urlencode({
+    data = urllib.parse.urlencode({
         'results': json.dumps(results),
         'params': json.dumps(params)
     })
-    req = urllib2.Request('{task_url}/{task_name}/results.json'.format(task_url=task_url, task_name=task_name), data)
-    response = urllib2.urlopen(req)
+    req = urllib.request.Request('{task_url}/{task_name}/results.json'.format(task_url=task_url, task_name=task_name), data)
+    response = urllib.request.urlopen(req)
     response_dict = json.loads(response.read())
     hints = response_dict.get('hints', [])
-    hints = [u'status: ' + response_dict.get('status', '')] + hints
-    return response_dict.get('result', 'No result'), u"\n".join(hints) 
+    hints = ['status: ' + response_dict.get('status', '')] + hints
+    return response_dict.get('result', 'No result'), "\n".join(hints) 
 
 uploading_task_check_source = inspect.getsource(task_check)
 
@@ -33,7 +33,7 @@ dummy_gen_params_source = inspect.getsource(gen_params)
 
 if __name__ == '__main__':
     if len(sys.argv) < 2:
-        print u"Usage: {0} <task_dir> [task_name]".format(sys.argv[0])
+        print("Usage: {0} <task_dir> [task_name]".format(sys.argv[0]))
         exit(1)
     dirname = sys.argv[1]
     fname = os.path.join(dirname, 'task.py')
@@ -43,12 +43,12 @@ if __name__ == '__main__':
         normpath = os.path.normpath(dirname)
         class_id = os.path.split(os.path.dirname(normpath))[-1]
         task_id = os.path.basename(normpath)
-    print(class_id, task_id)
+    print((class_id, task_id))
     db = pymongo.MongoClient(settings.DB_HOST).kpov
     try:
         db.authenticate(settings.USERNAME, settings.PASSWORD)
-    except Exception, e:
-        print "Not authenticated:"+str(e)
+    except Exception as e:
+        print("Not authenticated:"+str(e))
         #no auth or auth config?
     source = open(fname).read()
     code = compile(source, fname, 'exec')
@@ -56,7 +56,7 @@ if __name__ == '__main__':
     #    task, task_check, gen_params, prepare_disks, computers, params_meta.
     exec(code)
     public_meta = dict()
-    for k, v in params_meta.iteritems():
+    for k, v in params_meta.items():
         if v.get('public', False):
             public_meta[k] = v
     task_source = "\n\n".join([
@@ -67,10 +67,10 @@ if __name__ == '__main__':
     task_check_source = inspect.getsource(task_check)
     gen_params_source = inspect.getsource(gen_params)
     prepare_disks_source = inspect.getsource(prepare_disks)
-    x = params_meta.keys() # check for existence
+    x = list(params_meta.keys()) # check for existence
     db.computers_meta.remove({'task_id': task_id, 'class_id': class_id})
     auto_networks = set([None])
-    for k, v in computers.iteritems():
+    for k, v in computers.items():
         for n in v.get('networks_interfaces', []):
             auto_networks.add(n.get('network', None))
         db.computers_meta.update({
@@ -81,7 +81,7 @@ if __name__ == '__main__':
     auto_networks.remove(None)
     db.networks.remove({'task_id': task_id, 'class_id': class_id})
     try:
-        net_list = networks.iteritems()
+        net_list = iter(networks.items())
     except:
         net_list = [(k, {'public': False}) for k in auto_networks]
     for k, v in net_list:
diff --git a/kpov_judge/create_disk_images.py b/kpov_judge/create_disk_images.py
index c9d433f..b3ea93d 100755
--- a/kpov_judge/create_disk_images.py
+++ b/kpov_judge/create_disk_images.py
@@ -22,7 +22,7 @@ def get_prepare_disks(db, class_id, task_id):
 def create_snapshot(class_id, task_id, student_id, disk_name, overwrite = True, cow = False):
     print(os.path.join(settings.DISK_TEMPLATE_PATH, disk_name) + '.*')
     template_paths = glob.glob(os.path.join(settings.DISK_TEMPLATE_PATH, disk_name) + '.*')
-    filtered_paths = filter((lambda x: os.path.splitext(x)[1] == '.' + settings.STUDENT_DISK_FORMAT), template_paths)
+    filtered_paths = list(filter((lambda x: os.path.splitext(x)[1] == '.' + settings.STUDENT_DISK_FORMAT), template_paths))
     if filtered_paths:
         template_path = filtered_paths[0]
     else:
@@ -60,13 +60,13 @@ def publish_snapshot(d):
  
 if __name__ == '__main__':
     if len(sys.argv) != 1:
-        print "Usage: {0}"
-        print "Create the pending disk images"
+        print("Usage: {0}")
+        print("Create the pending disk images")
     db = pymongo.MongoClient(settings.DB_HOST).kpov
     try:
         db.authenticate(settings.USERNAME, settings.PASSWORD)
-    except Exception, e:
-        print str(e)
+    except Exception as e:
+        print(str(e))
     dev_prefix = settings.GUESTFS_DEV_PREFIX
     l = db.student_computers.find({"disk_urls": {"$exists": False}})
     computers_by_class_task_student = dict()
@@ -75,9 +75,10 @@ if __name__ == '__main__':
         if (class_id, task_id, student_id) not in computers_by_class_task_student:
             computers_by_class_task_student[(class_id, task_id, student_id)] = list()
         computers_by_class_task_student[(class_id, task_id, student_id)].append(computer)
-    for (class_id, task_id, student_id), computers in computers_by_class_task_student.items():
-        print "Creating {}/{} for {}".format(class_id, task_id, student_id)
-    	l = db.student_computers.find_one({'class_id': class_id, 'task_id': task_id, 'student_id':student_id, "disk_urls": {"$exists": False}})
+
+    for (class_id, task_id, student_id), computers in list(computers_by_class_task_student.items()):
+        print("Creating {}/{} for {}".format(class_id, task_id, student_id))
+        l = db.student_computers.find_one({'class_id': class_id, 'task_id': task_id, 'student_id':student_id, "disk_urls": {"$exists": False}})
         if l is None:
             continue
         lock_file = os.path.join(settings.STUDENT_LOCKFILE_PATH, 
@@ -160,9 +161,9 @@ if __name__ == '__main__':
             g.umount_all()
             g.close()
         lock_fp.write("saving URLs\n")
-        for comp_name, d_dict in all_disks.iteritems():
+        for comp_name, d_dict in all_disks.items():
             disk_urls = list()
-            for d_name, d in d_dict.iteritems():
+            for d_name, d in d_dict.items():
                 lock_fp.write('publishing '+ str(d) + '\n')
                 url = publish_snapshot(d)
                 lock_fp.write('published as '+ url + '\n')
diff --git a/kpov_judge/instructions_extractor.py b/kpov_judge/instructions_extractor.py
index 4e00dc5..b1644b2 100644
--- a/kpov_judge/instructions_extractor.py
+++ b/kpov_judge/instructions_extractor.py
@@ -8,27 +8,27 @@ import sys
 
 def print_instructions(p, fname):
     try:
-        print "---------------"
+        print("---------------")
         l = p.split(os.sep)
         l1 = []
-        for i in xrange(len(l)):
+        for i in range(len(l)):
             f = os.path.join(*l[:i+1])
             if os.path.islink(f):
                 s = "{0} ({1})".format(l[i], os.path.split(os.readlink(f))[1])
             else:
                 s = l[i]
             l1.append(s)
-        print p
-        print " - ".join(l1)
+        print(p)
+        print(" - ".join(l1))
         with open(os.path.join(p, fname)) as f:
             task_code = compile(f.read(), fname, 'exec')
             exec(task_code)
-            for lang, text in instructions.iteritems():
+            for lang, text in instructions.items():
                 print("Language: {0}".format(lang))
                 print(text.encode('utf-8'))
                 print("")
-    except Exception, e:
-        print e
+    except Exception as e:
+        print(e)
         pass
 
 if __name__ == '__main__':
diff --git a/kpov_judge/kpov_random_helpers.py b/kpov_judge/kpov_random_helpers.py
index 5fb2593..491e7ce 100755
--- a/kpov_judge/kpov_random_helpers.py
+++ b/kpov_judge/kpov_random_helpers.py
@@ -12,8 +12,8 @@ import glob
 import os
 
 def alnum_gen(r, l=1):
-    s = u""
-    for i in xrange(l):
+    s = ""
+    for i in range(l):
         s += r.choice(string.ascii_letters + string.digits)
     return s
 
@@ -70,8 +70,8 @@ def IPv4_net_gen(r, min_hosts=254, local=True, multicast=False):
 def IPv4_addr_gen(r, network, n_generated=1, reserve_top=1, reserve_bottom=1):
     net, mask = _net_to_int(network)
     hosts = []
-    l = r.sample(xrange(reserve_bottom, 
-        2**(32 - mask)-reserve_top), n_generated)
+    l = r.sample(list(range(reserve_bottom,
+        2**(32 - mask)-reserve_top)), n_generated)
     for i in l:
         hosts.append(socket.inet_ntoa(struct.pack('>I', net | i)))
     return hosts
@@ -79,7 +79,7 @@ def IPv4_addr_gen(r, network, n_generated=1, reserve_top=1, reserve_bottom=1):
 def MAC_gen(r):
     s = "0123456789ABCDEF"
     return ":".join([r.choice(s) + r.choice("26AE")] + \
-        [r.choice(s) + r.choice(s) for i in xrange(5)])
+        [r.choice(s) + r.choice(s) for i in range(5)])
 
 common_file_extensions = ['jpg', 'png', 'txt', 'doc', 'cfg', 'pdf', 'odt', 'cpp', 'c', 'sh', 'java']
 def fname_gen(r, extension = True):
@@ -131,7 +131,7 @@ default_generators = {
 def default_gen(userID, param_meta):
     r = random.Random(userID)
     params = dict()
-    for name, meta in param_meta.iteritems():
+    for name, meta in param_meta.items():
         if meta.get('generated', False):
             params[name] = default_generators.get(
                 meta.get('type', None), unknown_generator)(r)
@@ -139,6 +139,6 @@ def default_gen(userID, param_meta):
 
 if __name__ == '__main__':
     r = random.Random()
-    for k, v in default_generators.iteritems():
-        print ("---{}---".format(k))
-        print (v(r))
+    for k, v in default_generators.items():
+        print("---{}---".format(k))
+        print(v(r))
diff --git a/kpov_judge/rm_task.py b/kpov_judge/rm_task.py
index ebdadc6..117b3f1 100755
--- a/kpov_judge/rm_task.py
+++ b/kpov_judge/rm_task.py
@@ -14,14 +14,14 @@ import os
 
 if __name__ == '__main__':
     if len(sys.argv) < 2:
-        print u"Usage: {0} [task_name]".format(sys.argv[0])
+        print("Usage: {0} [task_name]".format(sys.argv[0]))
         exit(1)
     task_id = sys.argv[1]
     db = pymongo.MongoClient(settings.DB_HOST).kpov
     try:
         db.authenticate(settings.USERNAME, settings.PASSWORD)
-    except Exception, e:
-        print "Not authenticated:"+str(e)
+    except Exception as e:
+        print("Not authenticated:"+str(e))
         #no auth or auth config?
     db.computers_meta.remove({'task_id': task_id})
     db.networks.remove({'task_id': task_id})
diff --git a/kpov_judge/tasks/basic_network_gcc/task.py b/kpov_judge/tasks/basic_network_gcc/task.py
index eeb7d1c..ae690f0 100644
--- a/kpov_judge/tasks/basic_network_gcc/task.py
+++ b/kpov_judge/tasks/basic_network_gcc/task.py
@@ -8,7 +8,7 @@
 # - switch to a real SSH/SFTP client to properly handle filenames
 
 instructions = {
-    'si': u'''
+    'si': '''
 Postavite dva navidezna računalnika - SimpleArbiter in Student.
 Oba naj bosta povezana na internet. Poleg tega mora biti
 Student na naslovu {student_IP} dostopen s SimpleArbiter.
@@ -31,7 +31,7 @@ Napišite skripto ali program {P_script} v domačem imeniku uporabnika student,
 
 Lastnik vseh ustvarjenih datotek mora biti uporabnik student. 
 Gesla uporabnika student (vaje) ne smete spreminjati.''',
-    'en': u'''
+    'en': '''
 ''',
 }
 
@@ -124,10 +124,10 @@ def task(student_IP, net_prog_name,
     conn.login(student_IP, 'student', 'vaje')
     results = dict()
     r = random.Random(int(param_gen_seed))
-    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(11)])
+    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(11)])
     
-    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(13)])
-    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(17)])
+    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(13)])
+    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(17)])
     conn.sendline('ls -l {}'.format(P_script))
     conn.prompt()
     results['script_ls'] = conn.before
@@ -157,8 +157,8 @@ def gen_params(user_id, params_meta):
     r = random.Random(user_id+'evil cornholio')
     params = kpov_random_helpers.default_gen(user_id, params_meta)
     homedir = '/home/student/'
-    params['env_c'] = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ') for i in xrange(5)])
-    params['P_c'] = "".join([r.choice('abcdefghijklmnoprst') for i in xrange(5)]) + ".c"
+    params['env_c'] = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ') for i in range(5)])
+    params['P_c'] = "".join([r.choice('abcdefghijklmnoprst') for i in range(5)]) + ".c"
     params['param_gen_seed'] = str(r.randint(0, 2**24))
     params['c_destroy_gen_seed'] = str(r.randint(0, 2**24))
     dest_net = kpov_random_helpers.IPv4_subnet_gen(r, '10.0.2.128/26', 26)
@@ -175,7 +175,7 @@ def task_check(results, params):
         r = 0
         arg_len = len(arg)
         env_len = len(var)
-        for i in xrange(100):
+        for i in range(100):
             s_out += chr(32 + ((ord(arg[i % arg_len]) ^ ord(var[i % env_len])) % 64))
             r += ord(arg[i % arg_len]) + ord(var[i % env_len]) + i;
             if (i % 17 == 0):
@@ -192,9 +192,9 @@ def task_check(results, params):
     score = 0
     hints = []
     r = random.Random(int(params['param_gen_seed']))
-    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(11)])
-    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(13)])
-    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(17)])
+    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(11)])
+    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(13)])
+    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(17)])
     expected_script_stdout, expected_script_stderr, rval = test_out_gen(
         params['arg_c'], env_val 
         )
@@ -292,7 +292,7 @@ done; }&
     sh_path = r.choice(['/usr/share/doc', '/var/lib', '/usr/local/share', '/etc/alternatives'])
     sh_file = sh_path + '/' + params['net_prog_name']
     d.write(sh_file, evil_shell_source)
-    d.chmod(0775, sh_file)
+    d.chmod(0o775, sh_file)
     d.write("/etc/rc.local", """#!/bin/sh -e
 export PATH=$PATH:{}
 {} &
diff --git a/kpov_judge/tasks/copy_rename_100_files/task.py b/kpov_judge/tasks/copy_rename_100_files/task.py
index 2c3700f..9ad4d66 100644
--- a/kpov_judge/tasks/copy_rename_100_files/task.py
+++ b/kpov_judge/tasks/copy_rename_100_files/task.py
@@ -8,14 +8,14 @@
 # - switch to a real SSH/SFTP client to properly handle filenames
 
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari dva navidezna računalnika. Za prvega uporabi sliko diska simpleArbiterDhcp. Na drugem računalniku
 ustvari uporabnika test z geslom test.
 Na sliki diska simpleArbiterDhcp najdeš imenik s 100 datotekami. Prekopiraj vse datoteke na drugi računalnik v domači imenik uporabnika test.
 Spremeni vsebino datotek tako, da vse male črke spremeniš v velike.  Poskrbi, da se bo s prvega računalnika (simpleArbiterDhcp) mogoče prek
 ssh prijaviti na drugi računalnik in prebrati predelane datoteke.
 """,
-    'en': u'''
+    'en': '''
 Create two virtual machines. For the first, use the `simpleArbiterDhcp' image.
 On the second machine, create a user `test' with the password `test'.
 The `simpleArbiterDhcp' disk image contains a folder with 100 files. Copy all
diff --git a/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py b/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py
index e82e8ca..7e3c3c8 100644
--- a/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py
+++ b/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py
@@ -4,7 +4,7 @@
 
 # TODO (polz): 
 instructions = {
-    'si':u"""
+    'si':"""
 Prijavi se na sistem kot uporabnik student z geslom vaje.
 V domači mapi najdeš imenik {file_rename_dirname} z 20 datotekami.
   - Preimenuj vse datoteke tako, da zamenjaš minuse s podčrtaji
@@ -32,7 +32,7 @@ V domači mapi najdeš imenik {file_rename_dirname} z 20 datotekami.
     v novo vrstico v count.txt in rezultat zapiši v novo datoteko - lines.txt 
     v istem imeniku.
 """,
-	'en':u"""
+	'en':"""
 Log into the system as student using vaje as your password.
 In your home folder you will find a directory called {file_rename_dirname} 
     containing 20 files.
@@ -210,13 +210,13 @@ def gen_params(user_id, params_meta):
     r = random.Random(user_id)
     params['file_creator_random_seed'] = str(r.random())
     params['file_rename_dirname'] = homedir + kpov_random_helpers.default_generators['dirname'](r)
-    params['mv_src_dir'] = homedir + "".join([r.choice("abcdefgh") for i in xrange(6)])
-    params['mv_dst_dir'] = homedir + "".join([r.choice("ijklmnop") for i in xrange(6)])
+    params['mv_src_dir'] = homedir + "".join([r.choice("abcdefgh") for i in range(6)])
+    params['mv_dst_dir'] = homedir + "".join([r.choice("ijklmnop") for i in range(6)])
     params['syslog_n_zmeda'] = str(r.randint(5, 15))
     params['cowsay_string'] = kpov_random_helpers.default_generators['short_text'](r)
     params['curl_fname'] = kpov_random_helpers.default_generators['filename'](r)
     params['curl_n_images'] = str(r.randint(30,100))
-    params['wc_dirname'] = homedir + "".join([r.choice("rstuvxz") for i in xrange(8)])
+    params['wc_dirname'] = homedir + "".join([r.choice("rstuvxz") for i in range(8)])
     params['wc_n_lines'] = str(r.randint(200, 600))
     #params['phttp'] = "8080"
     #params['images'] = subprocess.check_output(["echo","$images"])
@@ -229,8 +229,8 @@ def task_check(results, params):
     hints = []
     r = random.Random(params['file_creator_random_seed'])
     fnames = []
-    for i in xrange(20):
-        fnames.append("".join([ r.choice("_abcdefghijk") for j in xrange(8)]))
+    for i in range(20):
+        fnames.append("".join([ r.choice("_abcdefghijk") for j in range(8)]))
     #TO FINISH SCORING WE REQUIRE DICT KEYS AND FUNCTIONS gen_params AND task TO BE FINISHED
     #POINTS FOR EACH TASK MAY BE ADJUSTED IN THE FUTURE
     #TASK 1
@@ -251,8 +251,8 @@ def task_check(results, params):
     # premakni datoteke s cim krajsim ukazom
     fnames = []
     try:
-        for i in xrange(40):
-            fnames.append("".join([ r.choice("123456789abcdefghijk") for j in xrange(8)]))
+        for i in range(40):
+            fnames.append("".join([ r.choice("123456789abcdefghijk") for j in range(8)]))
         task2_re = re.search(
             r"-rw[x-][r-][w-][x-][r-][w-][x-] \d* student student (\d*) .*mv_ukaz",
             results['mv_ls_size'])
@@ -280,17 +280,17 @@ def task_check(results, params):
     # 
     task3_ok = True
     mama_fnames = []
-    for i in xrange(20):
-        mama_fnames.append("".join([ r.choice("123456789abcdefghijk") for j in xrange(8)]))
+    for i in range(20):
+        mama_fnames.append("".join([ r.choice("123456789abcdefghijk") for j in range(8)]))
     papa_fnames = []
-    for i in xrange(20):
-        papa_fnames.append("".join([ r.choice("123456789abcdefghijk") for j in xrange(8)]))
+    for i in range(20):
+        papa_fnames.append("".join([ r.choice("123456789abcdefghijk") for j in range(8)]))
     dirnames = []
-    for i in xrange(20):
-        dirnames.append("".join([ r.choice("123456789abcdefghijk") for j in xrange(8)]))
+    for i in range(20):
+        dirnames.append("".join([ r.choice("123456789abcdefghijk") for j in range(8)]))
     linknames = []
-    for i in xrange(20):
-        linknames.append("".join([ r.choice("123456789abcdefghijk") for j in xrange(8)]))
+    for i in range(20):
+        linknames.append("".join([ r.choice("123456789abcdefghijk") for j in range(8)]))
     #print( results['grep_mama'])
     #print( results['grep_napake'])
     for i in dirnames + linknames + papa_fnames:
@@ -356,17 +356,17 @@ def prepare_disks(templates, task_params, global_params):
     # rename
     d.mkdir(task_params['file_rename_dirname'])
     d.chown(1000, 1000, task_params['file_rename_dirname'])
-    for i in xrange(20):
+    for i in range(20):
         fname = task_params['file_rename_dirname'] + '/' + "".join(
-            [r.choice("-abcdefghijk") for j in xrange(8)])
+            [r.choice("-abcdefghijk") for j in range(8)])
         d.touch(fname)
         d.chown(1000, 1000, fname)
     # mv ukaz
     d.mkdir(task_params['mv_src_dir'])
     d.chown(1000, 1000, task_params['mv_src_dir'])
-    for i in xrange(40):
+    for i in range(40):
         fname = task_params['mv_src_dir'] + '/' +"".join(
-            [r.choice("123456789abcdefghijk") for j in xrange(8)])
+            [r.choice("123456789abcdefghijk") for j in range(8)])
         d.touch(fname)
         d.chown(1000, 1000, fname)
     d.mkdir(task_params['mv_dst_dir'])
@@ -374,27 +374,27 @@ def prepare_disks(templates, task_params, global_params):
     # grep mama
     # mama fnames
     d.mkdir('/home/student/grep_test_dir')
-    for i in xrange(20):
+    for i in range(20):
         d.write("/home/student/grep_test_dir/" + "".join(
-            [ r.choice("123456789abcdefghijk") for j in xrange(8)]),
+            [ r.choice("123456789abcdefghijk") for j in range(8)]),
             "mama")
     # papa fnames
-    for i in xrange(20):
+    for i in range(20):
         d.write("/home/student/grep_test_dir/" + "".join(
-            [ r.choice("123456789abcdefghijk") for j in xrange(8)]),
+            [ r.choice("123456789abcdefghijk") for j in range(8)]),
             "papa")
     # dirnames
-    for i in xrange(20):
+    for i in range(20):
         d.mkdir("/home/student/grep_test_dir/" + "".join(
-            [ r.choice("123456789abcdefghijk") for j in xrange(8)]))
+            [ r.choice("123456789abcdefghijk") for j in range(8)]))
     # linknames
-    for i in xrange(20):
+    for i in range(20):
         d.ln_sf("mali zeleni", "/home/student/grep_test_dir/" + "".join(
-            [ r.choice("123456789abcdefghijk") for j in xrange(8)]))
+            [ r.choice("123456789abcdefghijk") for j in range(8)]))
     # sledenje syslog
     spammer_source = "#!/bin/sh\n" + int(task_params['syslog_n_zmeda']) * "logger zmeda\n"
     d.write("/usr/local/bin/syslog_spammer", spammer_source)
-    d.chmod(0775, "/usr/local/bin/syslog_spammer")
+    d.chmod(0o775, "/usr/local/bin/syslog_spammer")
     # curl
     l1 = ['images'] * int(task_params['curl_n_images'])
     l2 = ['imeges'] * r.randint(30, 100)
diff --git a/kpov_judge/tasks/custom_rdate/rDate.py b/kpov_judge/tasks/custom_rdate/rDate.py
index 1ceafaa..97885b0 100644
--- a/kpov_judge/tasks/custom_rdate/rDate.py
+++ b/kpov_judge/tasks/custom_rdate/rDate.py
@@ -14,5 +14,5 @@ podatek = s.recv(4)
 stevilka = struct.unpack("!I", podatek)
 st= stevilka[0]-220898800
 date = time.localtime(st)
-print(time.strftime('%Y-%m-%d %H:%M:%S'),date)
+print((time.strftime('%Y-%m-%d %H:%M:%S'), date))
 s.send(date)
diff --git a/kpov_judge/tasks/custom_rdate/task.py b/kpov_judge/tasks/custom_rdate/task.py
index 867e037..b84a2b7 100644
--- a/kpov_judge/tasks/custom_rdate/task.py
+++ b/kpov_judge/tasks/custom_rdate/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 # TODO: finish this!
 instructions = {
-    'si':u"""
+    'si':"""
 Postavite dva navidezna racunalnika: 
 - SimpleArbiterDhcpRdate s slike diska simpleArbiterRdate ter 
 - rdateClient.
@@ -18,7 +18,7 @@ predznaceno celo število, pri čemer naj uporablja zapis z debelim koncem
 (big endian).
 Število naj program izpiše na standardni izhod v obliki niza.
 """,
-    'en':u"""
+    'en':"""
 Setup two virtual machines: 
 - SimpleArbiterDhcpRdate from disk image simpleArbiterRdate and 
 - rdateClient.
@@ -69,9 +69,9 @@ networks = { 'net1': {'public': False}, 'test-net': {'public': True} }
 
 # Tu sem dolocil parametre
 params_meta = {
-    'RDATE_OFFSET':{'descriptions': {'si': u'Napaka v času pri rdate', 'en': 'Timekeeping error for rdate'}, 'w': False, 'public': False, 'type': 'integer', 'generated': True},
-    'PROGRAM_FILENAME':{'descriptions': {'si': u'Ime programa', 'en': 'program filename'}, 'w': False, 'public': True, 'type': 'integer', 'generated': True},
-    'IP_RDATECLIENT':{'descriptions': {'si': u'IP rdateClient', "en": "rdateClient's IP"}, 'w': True, 'public': True, 'type': 'IP', 'generated': False},
+    'RDATE_OFFSET':{'descriptions': {'si': 'Napaka v času pri rdate', 'en': 'Timekeeping error for rdate'}, 'w': False, 'public': False, 'type': 'integer', 'generated': True},
+    'PROGRAM_FILENAME':{'descriptions': {'si': 'Ime programa', 'en': 'program filename'}, 'w': False, 'public': True, 'type': 'integer', 'generated': True},
+    'IP_RDATECLIENT':{'descriptions': {'si': 'IP rdateClient', "en": "rdateClient's IP"}, 'w': True, 'public': True, 'type': 'IP', 'generated': False},
 }
 
 def task(IP_RDATECLIENT, PROGRAM_FILENAME):
@@ -90,7 +90,7 @@ def task(IP_RDATECLIENT, PROGRAM_FILENAME):
     client.connect(IP_RDATECLIENT, username=peer_user, password=peer_passwd)
     #client.login(IP_RDATECLIENT, peer_user, peer_passwd)
     r = random.Random(PROGRAM_FILENAME)
-    for i in xrange(10):
+    for i in range(10):
         stdin, stdout, stderr = client.exec_command(
             '~/{}'.format(PROGRAM_FILENAME))
         data = struct.pack("!I", r.randint(0, 2**32))
@@ -128,7 +128,7 @@ def task_check(results, params):
     r = random.Random(params['PROGRAM_FILENAME'])
     score = 0.0
     hints = []
-    for i in xrange(10):
+    for i in range(10):
         data = base64.decodestring(results['in_' + str(i)])
         x = struct.pack("!I", r.randint(0, 2**32))
         if data != x:
@@ -174,5 +174,5 @@ t = time.time() + 2208988800 + offset
 sys.stdout.write(struct.pack("!I", int(t)))
 """
     d.write('/usr/local/bin/kpovrdate', s2)
-    d.chmod(0775, '/usr/local/bin/kpovrdate')
+    d.chmod(0o775, '/usr/local/bin/kpovrdate')
     write_default_config(templates['simpleArbiterDhcpGWRdate'], global_params)
diff --git a/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py b/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py
index e46e6b8..40507d5 100644
--- a/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py
+++ b/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari tri navidezne računalnike. Za enega (SimpleArbiter) uporabi sliko diska simpleArbiter. Na drugega (DHCP_server) postavi strežnika DHCP in DNS in poskrbi, da ta računalnik dobi IP naslov {IP_server}. Poskrbi, da bo preostali računalnik (DHCP_client) dobil naslov {IP_client}, ki mu ga določi DHCP strežnik. Poskrbi še,da DNS strežnik vrne za hostname {HOSTNAME_X} IP naslov {IP_X}.
 """
 }
@@ -102,7 +102,7 @@ def gen_params(user_id, params_meta):
     r = random.Random(user_id+"bla")
     net = kpov_random_helpers.IPv4_subnet_gen(r, '172.23.128.0/18', 24)
     params['IP_server'], params['IP_client'], params['IP_X'] = kpov_random_helpers.IPv4_addr_gen(r, net, 3)
-    params['HOSTNAME_X'] = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ') for i in xrange(5)])
+    params['HOSTNAME_X'] = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ') for i in range(5)])
     return params
 
 
diff --git a/kpov_judge/tasks/edit_find_grep_compile_convert/task.py b/kpov_judge/tasks/edit_find_grep_compile_convert/task.py
index 7a358b9..3d9aafa 100644
--- a/kpov_judge/tasks/edit_find_grep_compile_convert/task.py
+++ b/kpov_judge/tasks/edit_find_grep_compile_convert/task.py
@@ -9,7 +9,7 @@
 
 
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari dva navidezna računalnika s slikama diskov 
 - SimpleArbiter s sliko diska simpleArbiterDhcp in 
 SmallStudent s sliko diska student-entrance2.
@@ -33,7 +33,7 @@ Program naj prebere znak s standardnega vhoda.
 Če je B-ti bit nastavljen na 0, naj program izpiše "ti".
 Program poimenuj {progname} in ga spravi v domači imenik {testuser}.
 """,
-    'en': u'''
+    'en': '''
 Create two virtual machines
 - SimpleArbiter using simpleArbiterDhcp as the disk image and
 SmallStudent using student-entrance2 as its disk.
@@ -275,31 +275,31 @@ def task_check(results, params):
                 break
         hints += ["wrong file contents\n" + str(diff_pos[1])]
         #hints += ["wrong file contents"]
-    expected_ls = u"ls -l ~/{dstfile}\r\n-rw--w---- 1 {testuser} bilbo .*{dstfile}.*\r\n".format(**params)
+    expected_ls = "ls -l ~/{dstfile}\r\n-rw--w---- 1 {testuser} bilbo .*{dstfile}.*\r\n".format(**params)
     if re.match(expected_ls, results["dst_ls"]):
         score += 3
     else:
-        hints += [u"missing file or wrong user/permissions\n" + results["dst_ls"]]
+        hints += ["missing file or wrong user/permissions\n" + results["dst_ls"]]
     if results["home_ls"].find(params['progname']) > -1:
         score += 2
     else:
         hints += ["missing program"]
-    expected_tita = u""
+    expected_tita = ""
     r = random.Random(params['pubseed'])
     for i in range(N_TITA):
         b = r.randint(0, 7)
         x_i = r.randint(37, 127)
         x = oct(x_i).replace('o', '')
-        expected_tita += u'echo -e "\\{}" | ~/{} {}\r\n'.format(x, params['progname'], b)
+        expected_tita += 'echo -e "\\{}" | ~/{} {}\r\n'.format(x, params['progname'], b)
         if x_i & (1 << b):
-            expected_tita += u"ta\r\n"
+            expected_tita += "ta\r\n"
         else:
-            expected_tita += u"ti\r\n"
+            expected_tita += "ti\r\n"
     if results["tita_return"] == expected_tita:
         score += 2
     else:
         #hints += [u"program output incorrect\n" + results["tita_return"] + expected_tita]
-        hints += [u"program output incorrect\n" + results["tita_return"]]
+        hints += ["program output incorrect\n" + results["tita_return"]]
     return score, hints
 
 
diff --git a/kpov_judge/tasks/entrance_exam/task.py b/kpov_judge/tasks/entrance_exam/task.py
index 6984c7c..bfefbd1 100644
--- a/kpov_judge/tasks/entrance_exam/task.py
+++ b/kpov_judge/tasks/entrance_exam/task.py
@@ -1,2 +1,2 @@
-instructions = {'si': u"""
+instructions = {'si': """
 Reši pristopni kolokvij z visoko oceno.""" }
diff --git a/kpov_judge/tasks/isc_dhcp_live_boot/task.py b/kpov_judge/tasks/isc_dhcp_live_boot/task.py
index 15d150e..c5ac728 100644
--- a/kpov_judge/tasks/isc_dhcp_live_boot/task.py
+++ b/kpov_judge/tasks/isc_dhcp_live_boot/task.py
@@ -5,7 +5,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi štiri navidezne računalnike - simpleArbiter, DHCP_server,
 BootableClientA ter BootableClientB.
 
@@ -107,7 +107,7 @@ def task(IP_DHCP, IP_GW, MAC_BOOT, BOOT_FNAME):
     import pexpect
     import re
     import tftpy
-    import StringIO
+    import io
     import time
     results={}
     # TODO (polz): Please use pexpect instead of os.system, it's much nicer.
diff --git a/kpov_judge/tasks/ldap_import/task.py b/kpov_judge/tasks/ldap_import/task.py
index 654e810..0df173e 100644
--- a/kpov_judge/tasks/ldap_import/task.py
+++ b/kpov_judge/tasks/ldap_import/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari dva navidezna računalnika - SimpleArbiter z diskom simpleArbiterDhcp ter LDAPServer.
 Na LDAPServer namesti strežnik LDAP. Na SimpleArbiter preberi ime domene DOMENA,
 uporabniško ime BIND_DN ter geslo BIND_PASS. Poskrbi, da se bo lahko klient s simpleArbiterDhcp povezal na LDAP strežnik na LDAPServer.
diff --git a/kpov_judge/tasks/ldap_search/task.py b/kpov_judge/tasks/ldap_search/task.py
index 0e906ae..886bf07 100644
--- a/kpov_judge/tasks/ldap_search/task.py
+++ b/kpov_judge/tasks/ldap_search/task.py
@@ -7,7 +7,7 @@
 # 
 # TODO: finish this!
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari dva navidezna računalnika - SimpleArbiter z diskom simpleArbiterDhcp
 ter LDAPServer.
 
@@ -32,7 +32,7 @@ O = Organization
 OU = Organizational Unit
 DC = Domain Component
 """,
-    'en': u"""
+    'en': """
 Create two virtual machines - SimpleArbiter using the disk simpleArbiterDhcp
 and LDAPServer.
 
@@ -96,12 +96,12 @@ computers = {
 networks = { 'net1': {'public': False}, 'test-net': {'public': True} }
 
 params_meta = {
-    'LDAP_IP': {'descriptions': {'si': u'IP strežnika', 'en': 'Server IP'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
-    'DOMAIN': {'descriptions': {'si': u'Domena (poddomena kpov.lusy.fri.uni-lj.si)', 'en': 'Domain (subdomain of kpov.lusy.fri.uni-lj.si)'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
-    'LDAP_USERNAME': {'descriptions': {'si': u'Uporabniško ime v LDAP', 'en': 'Username in LDAP'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
-    'LDAP_PASSWORD': {'descriptions': {'si': u'Geslo v LDAP', 'en': 'LDAP password'}, 'w': False, 'public':True, 'type': 'password', 'generated': True},
-    'BIND_USERNAME': {'descriptions': {'si': u'Uporabniško ime za dostop do LDAP (bind)', 'en': 'Bind username in LDAP'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
-    'BIND_PASSWORD': {'descriptions': {'si': u'Geslo za dostop do LDAP (bind)', 'en': 'Bind password in LDAP'}, 'w': False, 'public':True, 'type': 'password', 'generated': True},
+    'LDAP_IP': {'descriptions': {'si': 'IP strežnika', 'en': 'Server IP'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
+    'DOMAIN': {'descriptions': {'si': 'Domena (poddomena kpov.lusy.fri.uni-lj.si)', 'en': 'Domain (subdomain of kpov.lusy.fri.uni-lj.si)'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
+    'LDAP_USERNAME': {'descriptions': {'si': 'Uporabniško ime v LDAP', 'en': 'Username in LDAP'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
+    'LDAP_PASSWORD': {'descriptions': {'si': 'Geslo v LDAP', 'en': 'LDAP password'}, 'w': False, 'public':True, 'type': 'password', 'generated': True},
+    'BIND_USERNAME': {'descriptions': {'si': 'Uporabniško ime za dostop do LDAP (bind)', 'en': 'Bind username in LDAP'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
+    'BIND_PASSWORD': {'descriptions': {'si': 'Geslo za dostop do LDAP (bind)', 'en': 'Bind password in LDAP'}, 'w': False, 'public':True, 'type': 'password', 'generated': True},
 }
 
 def task(LDAP_IP, DOMAIN, LDAP_USERNAME, LDAP_PASSWORD, BIND_USERNAME, BIND_PASSWORD):
diff --git a/kpov_judge/tasks/mock_entrance_exam/task.py b/kpov_judge/tasks/mock_entrance_exam/task.py
index 52772a3..a6e3c8c 100644
--- a/kpov_judge/tasks/mock_entrance_exam/task.py
+++ b/kpov_judge/tasks/mock_entrance_exam/task.py
@@ -8,7 +8,7 @@
 # - switch to a real SSH/SFTP client to properly handle filenames
 
 instructions = {
-    'si': u'''
+    'si': '''
 Postavite dva navidezna računalnika - SimpleArbiter in Student.
 Oba naj bosta povezana na internet. Poleg tega mora biti
 Student na naslovu {student_IP} dostopen s SimpleArbiter.
@@ -28,7 +28,7 @@ Napišite skripto ali program {P_script} v domačem imeniku uporabnika student,
 
 Lastnik vseh ustvarjenih datotek mora biti uporabnik student. 
 Gesla uporabnika student (vaje) ne smete spreminjati.''',
-    'en': u'''Set up two virtual machines - SimpleArbiter and Student.
+    'en': '''Set up two virtual machines - SimpleArbiter and Student.
 Both should be connected to the Internet. Student should also be accessible
 from SimpleArbiter at the address {student_IP}.
 
@@ -142,10 +142,10 @@ def task(student_IP, net_prog_name,
     conn.login(student_IP, 'student', 'vaje')
     results = dict()
     r = random.Random(int(param_gen_seed))
-    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(11)])
+    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(11)])
     
-    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(13)])
-    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(17)])
+    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(13)])
+    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(17)])
     conn.sendline('ls -l {}'.format(P_script))
     conn.prompt()
     results['script_ls'] = conn.before
@@ -175,8 +175,8 @@ def gen_params(user_id, params_meta):
     r = random.Random(user_id+'evil cornholio')
     params = kpov_random_helpers.default_gen(user_id, params_meta)
     homedir = '/home/student/'
-    params['env_c'] = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ') for i in xrange(5)])
-    params['P_c'] = "".join([r.choice('abcdefghijklmnoprst') for i in xrange(5)]) + ".c"
+    params['env_c'] = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ') for i in range(5)])
+    params['P_c'] = "".join([r.choice('abcdefghijklmnoprst') for i in range(5)]) + ".c"
     params['param_gen_seed'] = str(r.randint(0, 2**24))
     params['c_destroy_gen_seed'] = str(r.randint(0, 2**24))
     dest_net = kpov_random_helpers.IPv4_subnet_gen(r, '10.0.2.128/26', 26)
@@ -193,7 +193,7 @@ def task_check(results, params):
         r = 0
         arg_len = len(arg)
         env_len = len(var)
-        for i in xrange(100):
+        for i in range(100):
             s_out += chr(32 + ((ord(arg[i % arg_len]) ^ ord(var[i % env_len])) % 64))
             r += ord(arg[i % arg_len]) + ord(var[i % env_len]) + i;
             if (i % 17 == 0):
@@ -210,9 +210,9 @@ def task_check(results, params):
     score = 0
     hints = []
     r = random.Random(int(params['param_gen_seed']))
-    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(11)])
-    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(13)])
-    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in xrange(17)])
+    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(11)])
+    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(13)])
+    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(17)])
     expected_script_stdout, expected_script_stderr, rval = test_out_gen(
         params['arg_c'], env_val 
         )
@@ -315,7 +315,7 @@ done;
     sh_path = r.choice(['/usr/share/doc', '/var/lib', '/usr/local/share', '/etc/alternatives'])
     sh_file = sh_path + '/' + task_params['net_prog_name']
     d.write(sh_file, evil_shell_source)
-    d.chmod(0775, sh_file)
+    d.chmod(0o775, sh_file)
     d.write("/etc/rc.local", """#!/bin/sh -e
 export PATH=$PATH:{}
 nohup {} &
diff --git a/kpov_judge/tasks/nat_port_forward/task.py b/kpov_judge/tasks/nat_port_forward/task.py
index 645b20f..2688268 100644
--- a/kpov_judge/tasks/nat_port_forward/task.py
+++ b/kpov_judge/tasks/nat_port_forward/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi tri računalnike - SimpleArbiter z diska simpleArbiter, TestClient z diska testClient in NATServer. NATServer naj ima dva omrežna vmesnika - z enim naj bo
 povezan na omrežje, od koder bo imel dostop do Interneta, z drugim pa na SimpleArbiter. TestClient naj bo povezan na isto omrežje z dostopom do Interneta kot NATServer.
 Poskrbi, da bo NATServer služil kot DHCP strežnik ter privzeti prehod za SimpleArbiter.
@@ -66,7 +66,7 @@ params_meta = {
     'IP_NAT': {'descriptions': {'si': 'Naslov NATServer, dostopen s TestClient'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
     'PORT_OUTER': {'descriptions': {'si': 'Zunanja vrata'}, 'w': False, 'public':True, 'type': 'port', 'generated': True},
     'PORT_INNER': {'descriptions': {'si': 'Notranja vrata'}, 'w': False, 'public': True, 'type': 'port', 'generated': True},
-    'NET': {'descriptions': {'si': u'Področje naslovov med SimpleArbiter in TestClient'}, 'w': False, 'public': True, 'type': 'NET', 'generated': True},
+    'NET': {'descriptions': {'si': 'Področje naslovov med SimpleArbiter in TestClient'}, 'w': False, 'public': True, 'type': 'NET', 'generated': True},
 }
 
 def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
@@ -86,7 +86,7 @@ def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
     k = r.randint(10, 15)
     results['pre_nc'] = str(k)
     results['nc_pre'] = ""
-    for i in xrange(k):
+    for i in range(k):
         sshconn.sendline("nc {} {}".format(IP_NAT, PORT_OUTER))
         sshconn.sendline()
         sshconn.sendintr()
@@ -96,7 +96,7 @@ def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
     sshconn.sendline()
     sshconn.prompt()
     sshconn.sendline("nc {} {}".format(IP_NAT, PORT_OUTER))
-    results['post_nc'] = "".join([r.choice("abcd\n") for i in xrange(100)])
+    results['post_nc'] = "".join([r.choice("abcd\n") for i in range(100)])
     sshconn.sendline(results['post_nc'])
     time.sleep(1)
     sshconn.sendintr()
@@ -126,7 +126,7 @@ def gen_params(user_id, params_meta):
 
 def task_check(results, params):
     import re
-    import cPickle
+    import pickle
     #if results is None:
     #    with open('bla.pickle') as f: 
     #        results = cPickle.load(f)
diff --git a/kpov_judge/tasks/nat_vlc/task.py b/kpov_judge/tasks/nat_vlc/task.py
index 59cceaa..cf3947b 100644
--- a/kpov_judge/tasks/nat_vlc/task.py
+++ b/kpov_judge/tasks/nat_vlc/task.py
@@ -9,7 +9,7 @@
 #TODO: finish this
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi dva navidezna računalnika - SimpleArbiter z diskom simpleArbiter
 ter NATServer. NATServer naj ima dva omrežna vmesnika - z enim naj bo povezan
 na lokalno omrežje, na katerem naj bo tudi simpleArbiter, z drugim pa na 
@@ -20,7 +20,7 @@ ustvarite še uporabnika {IP_NAT_user}.
 Poskrbi, da bo SimpleArbiter prek DHCP dobil naslov {IP_simple}.
 Poskrbi, da bo NATServer deloval kot prehod za SimpleArbiter in izvajal NAT.
 """,
-	'en':u"""
+	'en':"""
 Set up two virtual machines - SimpleArbiter (using the disc simpleArbiter) and
 NATServer. NATServer should have two network adapters. Connect the first
 adapter to SimpleArbiter and the second adapter to the Internet. Configure the
diff --git a/kpov_judge/tasks/nat_vlc/video.py b/kpov_judge/tasks/nat_vlc/video.py
index 7593d43..3c21c82 100644
--- a/kpov_judge/tasks/nat_vlc/video.py
+++ b/kpov_judge/tasks/nat_vlc/video.py
@@ -31,7 +31,7 @@ bashCommand = "avconv -i video.mp4 -c:a copy video1.avi"
 os.system(bashCommand)
 
 # This loop will increas videos length by adding more picesec of the original video.
-last = input("Set video length in seconds: ")
+last = int(input("Set video length in seconds: "))
 bashCommand = "avconv -i concat:video.avi\|video1.avi -c copy video.avi"
 for i in range(0, last-2):
 	os.system(bashCommand)
diff --git a/kpov_judge/tasks/network_boot_custom_program/task.py b/kpov_judge/tasks/network_boot_custom_program/task.py
index 891bc4a..db011c9 100644
--- a/kpov_judge/tasks/network_boot_custom_program/task.py
+++ b/kpov_judge/tasks/network_boot_custom_program/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi tri navidezne računalnike - simpleArbiter, DHCP_server, DHCP_client.
 Na računalniku DHCP_server najdeš program A. DHCP_server nastavi tako, da se bo
 DHCP_client lahko zagnal prek mreže. Na datotečni sistem, s katerega
diff --git a/kpov_judge/tasks/openvpn_multiple_hops/task.py b/kpov_judge/tasks/openvpn_multiple_hops/task.py
index 32b1835..5e54a1f 100644
--- a/kpov_judge/tasks/openvpn_multiple_hops/task.py
+++ b/kpov_judge/tasks/openvpn_multiple_hops/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py

 

 instructions = {

-    'si':u"""

+    'si':"""

 Postavi 4 navidezne računalnike - SimpleArbiter z diska simpleArbiterDhcp, A, B ter C.

 Na računalnikih A, B in C ustvari uporabnika test z geslom test.

 Poskrbi, da bodo vsi štirje na istem navideznem fizičnem omrežju. Naslov omrežja (NET_PHYS) ter naslove

diff --git a/kpov_judge/tasks/openvpn_simple_smb/task.py b/kpov_judge/tasks/openvpn_simple_smb/task.py
index 1ff035b..2db4337 100644
--- a/kpov_judge/tasks/openvpn_simple_smb/task.py
+++ b/kpov_judge/tasks/openvpn_simple_smb/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi dva navidezna računalnika - SimpleArbiter z diska SimpleArbiterVPN ter
 VPNClient1. Poskrbite, da bosta povezana med seboj in v Internet.
 Na VPNClient1 namestite OpenVPN in program za nadzor nad virtualnimi napravami
@@ -20,7 +20,7 @@ Nato poskrbite, da bo na VPNClient1 na navideznem omrežju prek NFS omogočen
 dostop do imenika /home/test/{DIRNAME}.
 V ta imenik skopirajte datoteke, ki so prek SMB dostopne na SimpleArbiter.
 """,
-	'en':u"""
+	'en':"""
 Setup two virtual machines - SimpleArbiterVPN and a VPN client (VPNClient1). 
 Set the client's network up so that it has access to the internal network and
 the internet.
@@ -244,12 +244,12 @@ def task_check(results, params):
     # get r into the correct state
     r = random.Random(params['secret_random_seed'])
     s = "\n".join([
-        "".join([r.choice("0123456789abcdef") for i in xrange(32)])
-        for i in xrange(16)])
+        "".join([r.choice("0123456789abcdef") for i in range(32)])
+        for i in range(16)])
     keyfile = kpov_random_helpers.fname_gen(r, extension=False)
     # now check the filenames
     fnames_ok = True
-    for i in xrange(3):
+    for i in range(3):
         fname = kpov_random_helpers.fname_gen(r, False)
         foo = kpov_random_helpers.fortune(r, 4096)
         pos = results['SimpleArbiter_ls'].find(fname + '.txt')
@@ -299,8 +299,8 @@ def prepare_disks(templates, task_params, global_params):
     import random
     r = random.Random(task_params['secret_random_seed'])
     s = "\n".join([
-        "".join([r.choice("0123456789abcdef") for i in xrange(32)])
-        for i in xrange(16)])
+        "".join([r.choice("0123456789abcdef") for i in range(32)])
+        for i in range(16)])
     s = """#
 # 2048 bit OpenVPN static key
 #
@@ -318,7 +318,7 @@ iface tap0 inet static
     netmask 255.255.255.0
 """.format(task_params['IP_SimpleArbiterVPN'])
     templates['simpleArbiterDhcpGWVPN'].write_append("/etc/network/interfaces", netaddr_s) 
-    for i in xrange(3):
+    for i in range(3):
         fname = kpov_random_helpers.fname_gen(r, False)
         templates['simpleArbiterDhcpGWVPN'].write(
             "/srv/smb/" + fname + '.txt',
diff --git a/kpov_judge/tasks/openwrt/task.py b/kpov_judge/tasks/openwrt/task.py
index 0439700..057fb96 100644
--- a/kpov_judge/tasks/openwrt/task.py
+++ b/kpov_judge/tasks/openwrt/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi dva navidezna računalnika - simpleArbiter z diska SimpleArbiter ter
 OpenWRT z diska OpenWRT. Na disku OpenWRT je nameščena distribucija OpenWRT.
 Nastavi OpenWRT tako, da bo imel dva omrežna vmesnika - en naj bo povezan na Internet,
diff --git a/kpov_judge/tasks/public_ip_ssh/task.py b/kpov_judge/tasks/public_ip_ssh/task.py
index b8f1d87..a566aa5 100644
--- a/kpov_judge/tasks/public_ip_ssh/task.py
+++ b/kpov_judge/tasks/public_ip_ssh/task.py
@@ -6,7 +6,7 @@
 OrderedDict = SON
 
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari dva navidezna računalnika. Za disk enega (imenujmo ga SimpleArbiter) uporabite
 sliko diska Test. Na drugega (imenujmo ga A) namesti poljubno Linux distribucijo. Na SimpleArbiter
 preberi uporabniško ime in geslo uporabnika, ki ga moraš ustvariti na A. Poskrbi, da se bo novoustvarjeni
@@ -30,9 +30,9 @@ computers = {
 networks = { 'net1': {'public': True}, 'net2': {'public': True} }
 
 params_meta = {
-    'peer_ip': {'descriptions': {'si': u'Naslov ssh strežnika'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
-    'peer_user': {'descriptions': {'si': u'ime uporabnika'}, 'w': False, 'public': True, 'type': 'username', 'generated': True},
-    'peer_passwd': {'descriptions': {'si': u'geslo uporabnika'}, 'w': False, 'public': True, 'type': 'password', 'generated': True},
+    'peer_ip': {'descriptions': {'si': 'Naslov ssh strežnika'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
+    'peer_user': {'descriptions': {'si': 'ime uporabnika'}, 'w': False, 'public': True, 'type': 'username', 'generated': True},
+    'peer_passwd': {'descriptions': {'si': 'geslo uporabnika'}, 'w': False, 'public': True, 'type': 'password', 'generated': True},
 }
 
 def task(peer_ip, peer_user, peer_passwd):
@@ -50,7 +50,7 @@ def task_check(results, params):
     try:
         s.login(peer_ip, peer_user, peer_passwd)
         s.logout()
-    except Exception, e:
+    except Exception as e:
         return 0, [str(e)]
     return 10, []
 
diff --git a/kpov_judge/tasks/public_ssh_motd_http/task.py b/kpov_judge/tasks/public_ssh_motd_http/task.py
index 6ea4239..df6ba32 100644
--- a/kpov_judge/tasks/public_ssh_motd_http/task.py
+++ b/kpov_judge/tasks/public_ssh_motd_http/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Na internet postavi računalnik, ki bo dostopen prek ssh in http.
 Poskrbi, da bo na računalniku ustvarjen uporabnik test z geslom test. Ob prijavi naj se
 uporabniku v MOTD izpiše (le) zgodbica ali pesmica, ki vam je všeč, dolžine vsaj 50 znakov.
diff --git a/kpov_judge/tasks/radius_multiple_realms/task.py b/kpov_judge/tasks/radius_multiple_realms/task.py
index 407af21..c879d56 100644
--- a/kpov_judge/tasks/radius_multiple_realms/task.py
+++ b/kpov_judge/tasks/radius_multiple_realms/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi tri navidezne računalnike - SimpleArbiter z diska simpleArbiterDhcp,
 RadiusA ter RadiusB. Na simpleArbiterDhcp preberi imeni domen DOMENA_A ter DOMENA_B,
 uporabniški imeni USER_A in USER_B, gesli PASSWORD_A in PASSWORD_B ter skrivnosti
diff --git a/kpov_judge/tasks/radius_mysql_pam/task.py b/kpov_judge/tasks/radius_mysql_pam/task.py
index 8957c6b..a3f86f7 100644
--- a/kpov_judge/tasks/radius_mysql_pam/task.py
+++ b/kpov_judge/tasks/radius_mysql_pam/task.py
@@ -3,7 +3,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari dva navidezna računalnika - SimpleArbiter z diska simpleArbiterDhcp ter
 RadiusServer. Na RadiusServer namesti FreeRadius ter MySQL. 
 
@@ -26,7 +26,7 @@ Nastavi PAM za prijavo (login) tako, da bo dovolj, če se uporabnik na ssh
 predstavi z uporabniškim imenom in geslom, ki sta veljavna na FreeRadius,
 ne glede na /etc/shadow oziroma /etc/password.
 """,
-   'en':u"""
+   'en':"""
 Create two virtual machines - SimpleArbiter using the disk simpleArbiterDhcp
 and RadiusServer. On RadiusServer, install FreeRadius and MySQL.
 
@@ -89,10 +89,10 @@ networks = { 'net1': {'public': False}, 'test-net': {'public': True} }
 params_meta = {
     'IP_RS': {'descriptions': {'si': 'Naslov RadiusServer', 'en': 'RadiusServer IP address'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
     'RADIUS_SECRET':{'descriptions': {'si': 'Skrivnost RADIUS', 'en': 'RADIUS secret'}, 'w': False, 'public':True, 'type': 'password', 'generated': True},
-    'RADIUS_USERNAME': {'descriptions': {'si': u'Uporabniško ime', 'en': 'Username'}, 'w': True, 'public':True, 'type': 'username', 'generated': False},
-    'RADIUS_PASSWORD': {'descriptions': {'si': u'Geslo uporabnika', 'en': 'Password'}, 'w': False, 'public':True, 'type': None, 'generated': True},
-    'MYSQL_DB_NAME': {'descriptions': {'si': u'Ime baze v mysql', 'en': 'Database name'}, 'w': False, 'public':True, 'type': None, 'generated': True},
-    'MYSQL_ADMIN_USER':{'descriptions': {'si': u'Uporabniško ime za dostop do MySQL', 'en': 'MySQL username'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
+    'RADIUS_USERNAME': {'descriptions': {'si': 'Uporabniško ime', 'en': 'Username'}, 'w': True, 'public':True, 'type': 'username', 'generated': False},
+    'RADIUS_PASSWORD': {'descriptions': {'si': 'Geslo uporabnika', 'en': 'Password'}, 'w': False, 'public':True, 'type': None, 'generated': True},
+    'MYSQL_DB_NAME': {'descriptions': {'si': 'Ime baze v mysql', 'en': 'Database name'}, 'w': False, 'public':True, 'type': None, 'generated': True},
+    'MYSQL_ADMIN_USER':{'descriptions': {'si': 'Uporabniško ime za dostop do MySQL', 'en': 'MySQL username'}, 'w': False, 'public':True, 'type': 'username', 'generated': True},
     'MYSQL_ADMIN_PASSWORD': {'descriptions': {'si': 'Geslo za dostop do MySQL', 'en': 'MySQL password'}, 'w': True, 'public':True, 'type': 'password', 'generated': True},
     'MYSQL_SEED':{'descriptions': {'si': 'seed', 'en': 'seed'}, 'w': False, 'public':True, 'type': None, 'generated': True},
 }
@@ -169,8 +169,8 @@ def task_check(results, params):
         # print "Test OK"
         score += 2
     else:
-        hints.append(u'radtest connect output incorrect:' + results['Test_RadiusServer'])
-        print (results['Test_RadiusServer'], s)
+        hints.append('radtest connect output incorrect:' + results['Test_RadiusServer'])
+        print((results['Test_RadiusServer'], s))
     # Testiranje podatkovne base mysql
     s = "Welcome to the MySQL monitor.*Type 'help;' or '\\\\h' for help\\. Type '\\\\c' to clear the current input statement\\.\r\n"
     if re.search(s, results['mysql_login'], flags=re.DOTALL):
@@ -178,44 +178,44 @@ def task_check(results, params):
         score += 1
     else:
         hints.append("mysql connection string incorrect")
-        print (results['mysql_login'], s)
+        print((results['mysql_login'], s))
     s = " USE {MYSQL_DB_NAME}\r\nReading table information.*Database changed\r\n".format(**params)
     if re.search(s, results['database_connect'], flags=re.DOTALL):
         # print "database_connect OK"
         score += 1
     else:
         hints.append('mysql table information string incorrect')
-        print (results['database_connect'],)
+        print((results['database_connect'],))
     s = " SELECT UserName, Value FROM radcheck;\r\n.*{RADIUS_USERNAME} *| *{RADIUS_PASSWORD}".format(**params)
     if re.search(s, results['select_from_users'], flags=re.DOTALL):
         # print "select_from_users OK"
         score += 2
     else:
         hints.append('mysql user entry in table check failed')
-        print (results['select_from_users'], )
+        print((results['select_from_users'], ))
 
     s = r"Sent Access-Request Id [0-9]+ from ([0-9]|\.)+:[0-9]+ to {0}:1812 length [0-9]+\r\n\tUser-Name = \"{1}\"\r\n\tUser-Password = \"{2}\".*Access-Accept Id [0-9]+ from {0}".format(params['IP_RS'], MYSQL_TEST_USER, MYSQL_TEST_PASSWORD)
     if re.search(s, results['radtest_OK'], flags=re.DOTALL):
         # print "radtest_OK OK"
         score += 2
     else:
-        hints.append(u'radtest output incorrect:' + results['radtest_OK'])
-        print (s, results['radtest_OK'])
+        hints.append('radtest output incorrect:' + results['radtest_OK'])
+        print((s, results['radtest_OK']))
 
-    s = ur"Sent Access-Request Id [0-9]+ from ([0-9]|\.)+:[0-9]+ to {0}:1812 length [0-9]+\r\n\tUser-Name = \"{1}\"\r\n\tUser-Password = \"Flügzeug\".*Access-Reject Id [0-9]+ from {0}".format(params['IP_RS'], MYSQL_TEST_USER)
+    s = r"Sent Access-Request Id [0-9]+ from ([0-9]|\.)+:[0-9]+ to {0}:1812 length [0-9]+\r\n\tUser-Name = \"{1}\"\r\n\tUser-Password = \"Flügzeug\".*Access-Reject Id [0-9]+ from {0}".format(params['IP_RS'], MYSQL_TEST_USER)
     if re.search(s, results['radtest_NOK'], flags=re.DOTALL):
         # print "radtest_NOK OK"
         score += 1
     else:
-        hints.append(u'radtest negative output incorrect: ' + results['radtest_NOK'])
-        print (results['radtest_NOK'], s)
+        hints.append('radtest negative output incorrect: ' + results['radtest_NOK'])
+        print((results['radtest_NOK'], s))
     s = "{RADIUS_USERNAME}@.*:~\\$".format(**params)
     if re.search(s, results['login_test'], flags=re.DOTALL):
         # print "login_test OK"
         score += 1
     else:
         hints.append('login test failed')
-        print (results['login_test'],s)
+        print((results['login_test'],s))
     return score, hints
 
 def prepare_disks(templates, task_params, global_params):
diff --git a/kpov_judge/tasks/rdate_64bit/task.py b/kpov_judge/tasks/rdate_64bit/task.py
index 27d5e5f..87de002 100644
--- a/kpov_judge/tasks/rdate_64bit/task.py
+++ b/kpov_judge/tasks/rdate_64bit/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi dva navidezna računalnika - SimpleArbiter z diska simpleArbiterDhcp ter
 RdateServer. Na RdateServer postavi strežnik, ki bo poslušal na vratih VRATA_X.
 Vsakič, ko se na vrata poveže klient, naj strežnik pošlje število sekund od DATUM_X.
diff --git a/kpov_judge/tasks/rename_grep_network/task.py b/kpov_judge/tasks/rename_grep_network/task.py
index ce3661b..e8ce0b2 100644
--- a/kpov_judge/tasks/rename_grep_network/task.py
+++ b/kpov_judge/tasks/rename_grep_network/task.py
@@ -9,7 +9,7 @@
 
 
 instructions = {
-    'si': u"""
+    'si': """
 Ustvari dva navidezna računalnika s slikama diskov 
 - SimpleArbiterExam s sliko diska simpleArbiterDhcp in
 SmallStudent s slikama diska student-entrance3
@@ -32,7 +32,7 @@ Pazi, da nobena druga datoteka v domačem imeniku v svojem imenu ne bo vsebovala
 Poskrbi, da bo lastnik {testuser}, skupina pa naj ostane nespremenjena.
 Brati naj jo ima pravico samo lastnik, pisati lastnik in skupina, poganjati nihče.
 """,
-    'en': u'''
+    'en': '''
 ''',
 }
 
@@ -252,11 +252,11 @@ def task_check(results, params):
         hints += ["wrong file contents\n" + str(diff_pos[1])]
         #hints += ["wrong file contents"]
     params['dstfile'] = dstfile
-    expected_dst_ls = u"ls -l ~/\\*I\\*.txt\r\n-rw--w---- 1 {testuser} bilbo .*{dstfile}\r\n".format(**params)
+    expected_dst_ls = "ls -l ~/\\*I\\*.txt\r\n-rw--w---- 1 {testuser} bilbo .*{dstfile}\r\n".format(**params)
     if re.match(expected_dst_ls, results["dst_ls"]):
         score += 2
     else:
-        hints += [u"missing file or wrong user/permissions\n" + results["dst_ls"] + "\n" + expected_dst_ls]
+        hints += ["missing file or wrong user/permissions\n" + results["dst_ls"] + "\n" + expected_dst_ls]
     if results["home_ls"].find(params['dstfile']) > -1:
         score += 2
     expected_mnts = [
diff --git a/kpov_judge/tasks/set_ip_dhcp_hostname/task.py b/kpov_judge/tasks/set_ip_dhcp_hostname/task.py
index 63ba12a..f68c71b 100644
--- a/kpov_judge/tasks/set_ip_dhcp_hostname/task.py
+++ b/kpov_judge/tasks/set_ip_dhcp_hostname/task.py
@@ -5,7 +5,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari tri navidezne računalnike. Za disk prvega uporabi sliko diska simpleArbiterDhcp.
 Za enega od ostalih dveh (Z_DHCP) poskrbi, da bo dobil IP prek DHCP, pri čemer
 naj kot hostname strežniku pošlje ime, ki ga dobiš na simpleArbiterDhcp. 
diff --git a/kpov_judge/tasks/set_ip_static_dhcp/task.py b/kpov_judge/tasks/set_ip_static_dhcp/task.py
index c611356..0553585 100644
--- a/kpov_judge/tasks/set_ip_static_dhcp/task.py
+++ b/kpov_judge/tasks/set_ip_static_dhcp/task.py
@@ -3,7 +3,7 @@
 
 # kpov_random_helpers should be imported by add_assignment.py
 instructions = {
-    'si':u"""
+    'si':"""
 Ustvari tri navidezne racunalnike. Za prvega
 uporabi sliko diska simpleArbiterDhcpGW, za drugega sliko diska
 maliNetworkManager, za tretjega sliko diska maliBrezNetworkManager.
@@ -14,7 +14,7 @@ za omrežni vmesnik, temveč bosta delovala ukaza ifup in ifdown.
 Na maliNetworkManager nastavi IP naslov {IP_NM} ter DNS {DNS_NM}.
 Na maliBrezNetworkManager nastavi IP naslov {IP_static} ter DNS {DNS_static}.
 """,
-    'en':u"""Create three virtual machines. Use simpleArbiterDhcpGW as the
+    'en':"""Create three virtual machines. Use simpleArbiterDhcpGW as the
 disk image for the first, maliNetworkManager as the disk image for the second
 and maliBrezNetworkManager for the third. The virtual machine names can match
 the disks.
diff --git a/kpov_judge/tasks/set_motd/task.py b/kpov_judge/tasks/set_motd/task.py
index 0e862a6..eadcca7 100644
--- a/kpov_judge/tasks/set_motd/task.py
+++ b/kpov_judge/tasks/set_motd/task.py
@@ -6,7 +6,7 @@
 # OrderedDict = SON
 
 instructions = {
-    "si":u"""
+    "si":"""
 Ustvari dva navidezna računalnika - imenujmo ju SimpleArbiterDhcpGW in
 Student. Za računalnik SimpleArbiterDhcpGW uporabite sliko diska, poimenovano
 SimpleArbiterDhcpGW. 
@@ -25,7 +25,7 @@ vrstica oblike uporabnisko_ime@ime_racunalnika:~$ .
 Pazite, da se bo takšna vrstica pojavila šele po nizu, ki ste ga dobili v
 teh navodilih.
     """,
-    'en':u"""
+    'en':"""
 Create two virtual machines - named SimpleArbiterDhcpGW and Student. 
 For the 'SimpleArbiterDhcpGW', use disc image named SimpleArbiterDhcpGW.
 
@@ -68,10 +68,10 @@ computers = {
 networks = { 'net1': {'public': False}, 'test-net': {'public': True} }
 
 params_meta = {
-    'peer_ip': {'descriptions': {'si': u'IP računalnika', 'en':'IP'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
+    'peer_ip': {'descriptions': {'si': 'IP računalnika', 'en':'IP'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
     'peer_user': {'descriptions': {'si': 'ime uporabnika', 'en':'Username'}, 'w': False, 'public': True, 'type': 'username', 'generated': True},
     'peer_passwd': {'descriptions': {'si': 'geslo uporabnika', 'en': 'Password'}, 'w': True, 'public': True, 'type': 'alnumstr', 'generated': False},
-    'niz': {'descriptions':{'si': u'niz, ki naj se v motd pokaže', 'en': 'The string which should be displayed in the MOTD'}, 'w': False, 'public': True, 'type': 'short_text', 'generated': True},
+    'niz': {'descriptions':{'si': 'niz, ki naj se v motd pokaže', 'en': 'The string which should be displayed in the MOTD'}, 'w': False, 'public': True, 'type': 'short_text', 'generated': True},
 }
 
 def task(peer_ip, peer_user, peer_passwd, niz):
diff --git a/kpov_judge/tasks/smb_nfs/task.py b/kpov_judge/tasks/smb_nfs/task.py
index 7143cf0..5ea7695 100644
--- a/kpov_judge/tasks/smb_nfs/task.py
+++ b/kpov_judge/tasks/smb_nfs/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 # TODO: dokoncaj!
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi dva navidezna računalnika (simpleArbiterDhcp in FileServer).
 
 Poskrbi, da bo imenik {NFS_MOUNT} na FileServer dostopen prek NFS in 
@@ -13,7 +13,7 @@ Ime SMB strežnika nastavite na {FILESERVER_NAME}.
 
 SimpleArbiterDhcp naj ima prek NFS pravico pisati po imeniku.
 """,
-'en':u"""
+'en':"""
 Set up two virtual computers (simpleArbiterDhcp and FileServer).
 
 Make sure that the directory {NFS_MOUNT} on FileServer is accessible
diff --git a/kpov_judge/tasks/snmp_agent_uptime/task.py b/kpov_judge/tasks/snmp_agent_uptime/task.py
index 1ec037b..c636549 100644
--- a/kpov_judge/tasks/snmp_agent_uptime/task.py
+++ b/kpov_judge/tasks/snmp_agent_uptime/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 # TODO: finish this.
 instructions = {
-    'si':u"""
+    'si':"""
 Naloga: Postavi tri navidezne racunalnike: 
 - SimpleArbiter s sliko diska simpleArbiterDhcpGW,
 - SNMPServer in 
@@ -26,7 +26,7 @@ Postavi jo na SNMP klienta, v domaci imenik uporabnika test z geslom test.
 
 Poskrbi, da bodo podatki na SNMPServer dostopni za skupino (community) studentje.
 """,
-    'en':u"""
+    'en':"""
 Set up three virtual computers, SimpleArbiter with the disk image simpleArbiterDhcp,
 SNMPServer and SNMPClient. Write a program called upminutes. This program should output
 the uptime of the computer in minutes. Set it up on SNMPClient in the home directory
@@ -95,11 +95,11 @@ computers = {
 networks = { 'net1': {'public': False}, 'test-net': {'public': True} }
 
 params_meta = {
-    'SNMP_VALUE': {'descriptions': {'si': u'Vrednost, dostopna prek SNMP', 'en': 'The value available over SNMP'}, 'w': False, 'public':False, 'type': 'short', 'generated': True}, 
-    'SNMP_UPTIME_OID': {'descriptions': {'si': u'SNMP_UPTIME_OID (za uptime)', 'en': 'SNMP_UPTIME_OID (for the uptime)'}, 'w': False, 'public':True, 'type': 'str', 'generated': True}, 
-    'SNMP_CLIENT_OID': {'descriptions': {'si': u'SNMP_CLIENT_OID, ki naj ga klient bere', 'en':'The OID that the client should read'}, 'w': False, 'public':True, 'type': 'OID', 'generated': True}, 
-    'SERVER_IP': {'descriptions': {'si': u'IP SNMP strežnika', 'en':'IP of the SNMP server'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False}, 
-    'CLIENT_IP': {'descriptions': {'si': u'IP SNMP klienta', 'en': 'IP of the SNMP client'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False}, 
+    'SNMP_VALUE': {'descriptions': {'si': 'Vrednost, dostopna prek SNMP', 'en': 'The value available over SNMP'}, 'w': False, 'public':False, 'type': 'short', 'generated': True}, 
+    'SNMP_UPTIME_OID': {'descriptions': {'si': 'SNMP_UPTIME_OID (za uptime)', 'en': 'SNMP_UPTIME_OID (for the uptime)'}, 'w': False, 'public':True, 'type': 'str', 'generated': True}, 
+    'SNMP_CLIENT_OID': {'descriptions': {'si': 'SNMP_CLIENT_OID, ki naj ga klient bere', 'en':'The OID that the client should read'}, 'w': False, 'public':True, 'type': 'OID', 'generated': True}, 
+    'SERVER_IP': {'descriptions': {'si': 'IP SNMP strežnika', 'en':'IP of the SNMP server'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False}, 
+    'CLIENT_IP': {'descriptions': {'si': 'IP SNMP klienta', 'en': 'IP of the SNMP client'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False}, 
 
 }
 
@@ -131,8 +131,8 @@ def task(SERVER_IP, CLIENT_IP, SNMP_UPTIME_OID, SNMP_CLIENT_OID):
         return_results['server_OID'] = "\n".join(result_list)
     except Exception as exception_error:
             # Check for errors and print out results
-        print ('ERROR: Occurred during SNMPget for OID %s from %s: '
-                   '(%s)') % (SNMP_UPTIME_OID, CLIENT_IP, exception_error)
+        print(('ERROR: Occurred during SNMPget for OID %s from %s: '
+                   '(%s)') % (SNMP_UPTIME_OID, CLIENT_IP, exception_error))
         sys.exit(2)
  
     client.connect(CLIENT_IP, username='test', password='test')
@@ -194,7 +194,7 @@ def task_check(results, params):
             if oid.strip() == server_oid and d >= -2 and d <= 5:
                 found_uptime = True
                 break
-        except Exception, e:
+        except Exception as e:
             pass
     if len(lines) <= 50 and found_uptime:
         score += 3
@@ -232,5 +232,5 @@ if action != '-s' and oid == foo_oid:
     print "{val}"
 """.format(oid = task_params['SNMP_CLIENT_OID'], val = task_params['SNMP_VALUE'])
     templates['simpleArbiterDhcpGWSNMP'].write('/usr/local/bin/snmpext.py', prog)
-    templates['simpleArbiterDhcpGWSNMP'].chmod(0755, '/usr/local/bin/snmpext.py')
+    templates['simpleArbiterDhcpGWSNMP'].chmod(0o755, '/usr/local/bin/snmpext.py')
     write_default_config(templates['simpleArbiterDhcpGWSNMP'], global_params)
diff --git a/kpov_judge/tasks/snmp_alarms_interfaces/task.py b/kpov_judge/tasks/snmp_alarms_interfaces/task.py
index e37663a..516cc69 100644
--- a/kpov_judge/tasks/snmp_alarms_interfaces/task.py
+++ b/kpov_judge/tasks/snmp_alarms_interfaces/task.py
@@ -4,7 +4,7 @@
 # kpov_random_helpers should be imported by add_assignment.py
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavite tri računalnike - SimpleArbiterSNMP s sliko diska simpleArbiterSNMP, ServerSNMP s sliko
 diska serverSNMP ter SNMPClient.
 
diff --git a/kpov_judge/tasks/vlc_stream_rtp/task.py b/kpov_judge/tasks/vlc_stream_rtp/task.py
index 39b315f..5c8011b 100644
--- a/kpov_judge/tasks/vlc_stream_rtp/task.py
+++ b/kpov_judge/tasks/vlc_stream_rtp/task.py
@@ -6,7 +6,7 @@
 # TODO: finish this
 
 instructions = {
-    'si':u"""
+    'si':"""
 Postavi navidezni računalnik SimpleArbiter z diska simpleArbiter
 ter StudentVLC z diska student-VLC. Poskrbi, da bosta na istem omrežju, od
 koder bosta imela dostop tudi do Interneta Na StudentVLC posodobi datoteko 
@@ -17,7 +17,7 @@ lokalnem omrežju prek RTP z imenom toka {TOK} na naslovu {NASLOV}, vrata {PORT}
 Računaj, da bodo film lahko videli tvoji sošolci. Kršenje avtorskih pravic
 je pri reševanju te naloge strogo prepovedano.
 """,
-     'en':u"""
+     'en':"""
 Set up a virtual computer called SimpleArbiter using the simpleArbiter disk and
 a virtual computer called StudentVLC using the student-VLC disk. Make sure they
 are on the same network and that they have access to the Internet.
diff --git a/kpov_judge/test_prepare_disks.py b/kpov_judge/test_prepare_disks.py
index 6121be4..21844a0 100755
--- a/kpov_judge/test_prepare_disks.py
+++ b/kpov_judge/test_prepare_disks.py
@@ -10,7 +10,7 @@ import glob
 import subprocess
 import fcntl
 import paramiko
-import urllib2
+import urllib.request, urllib.error, urllib.parse
 import yaml
 from test_task import http_auth
 from util import write_default_config
@@ -144,9 +144,9 @@ class SSHGuestFs:
  
 if __name__ == '__main__':
     if len(sys.argv) != 1:
-        print "Usage: {0}"
-        print "Run prepare_disks on running computers over ssh"
-        print "The task name and params are read from ~/.kpov_params.yaml"
+        print("Usage: {0}")
+        print("Run prepare_disks on running computers over ssh")
+        print("The task name and params are read from ~/.kpov_params.yaml")
     yaml_config_file = os.path.expanduser("~/.kpov_params.yaml")
     with open(yaml_config_file) as f:
         params = yaml.load(f)
@@ -156,8 +156,8 @@ if __name__ == '__main__':
         task_name = params['task_name']
         if task_url.startswith('http'):
             http_auth(task_url, params['username'], params['password'])
-        req = urllib2.Request("{task_url}/{task_name}/task.py".format(**params))
-        source = urllib2.urlopen(req).read()
+        req = urllib.request.Request("{task_url}/{task_name}/task.py".format(**params))
+        source = urllib.request.urlopen(req).read()
         t = compile(source, 'task.py', 'exec')
         exec(t)
     except Exception as e:
@@ -166,20 +166,20 @@ if __name__ == '__main__':
     templates = dict()
     sshguestfs_params = params.get('sshguestfs_params', dict())
     task_sshguestfs_params = sshguestfs_params.get(task_name, dict())
-    for computer_name, computer in computers.iteritems():
+    for computer_name, computer in computers.items():
         comp_params = task_sshguestfs_params.get(computer_name, dict())
         for k in ['hostname', 'username', 'password']:
             try:
                 p = comp_params[k]
             except:
-                p = raw_input("{} {}:".format(computer_name, k))
+                p = input("{} {}:".format(computer_name, k))
             comp_params[k] = p
         comp_connection = None
         try:
             comp_connection = SSHGuestFs(**comp_params)
             task_sshguestfs_params[computer_name] = comp_params
-        except Exception, e:
-            print e
+        except Exception as e:
+            print(e)
             task_sshguestfs_params.pop(computer_name, None)
         for disk in computer['disks']:
             disk_name = disk['name']
diff --git a/kpov_judge/test_task.py b/kpov_judge/test_task.py
index 37033d2..4251b50 100755
--- a/kpov_judge/test_task.py
+++ b/kpov_judge/test_task.py
@@ -3,8 +3,8 @@
 
 import yaml
 import json
-import urllib
-import urllib2
+import urllib.request, urllib.parse, urllib.error
+import urllib.request, urllib.error, urllib.parse
 try:
     from dialog import Dialog
 except:
@@ -34,7 +34,7 @@ DEFAULT_LANGUAGE = 'si'
 or from a file."""
 def get_params_dialog(params, meta, param_name_list=None, dialog=None, language = None):
     if param_name_list is None:
-        param_name_list = meta.keys()
+        param_name_list = list(meta.keys())
     if language is None:
         language = params.get('language', DEFAULT_LANGUAGE)
     for name in param_name_list:
@@ -63,28 +63,28 @@ def get_params_dialog(params, meta, param_name_list=None, dialog=None, language
 
 def add_meta_to_argparser(argparser, meta, defaults = {}):
     language = defaults.get('language', DEFAULT_LANGUAGE)
-    for k, v in meta.iteritems():
+    for k, v in meta.items():
         try:
             desc = v['descriptions'][language].encode("utf-8")
         except:
             desc = k
         # print("{} {}".format(desc, type(desc)))
-        argparser.add_argument('--'+k, nargs='?', help=desc, type=unicode, default=defaults.get(k, None))
+        argparser.add_argument('--'+k, nargs='?', help=desc, type=str, default=defaults.get(k, None))
     return argparser
 
 def http_auth(url, username, password):
-    password_mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
+    password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
 # Add the username and password.
 # If we knew the realm, we could use it instead of None.
     password_mgr.add_password(None, url, username, password)
-    handler = urllib2.HTTPBasicAuthHandler(password_mgr)
+    handler = urllib.request.HTTPBasicAuthHandler(password_mgr)
 # create "opener" (OpenerDirector instance)
-    opener = urllib2.build_opener(handler)
+    opener = urllib.request.build_opener(handler)
 # use the opener to fetch a URL
 #    opener.open(SERVER_URL)
 # Install the opener.
 # Now all calls to urllib2.urlopen use our opener.
-    urllib2.install_opener(opener)
+    urllib.request.install_opener(opener)
 
 def load_task(stream):
     # the stream should compile into at least the function
@@ -110,7 +110,7 @@ def locate_task(params, argparser, dialog):
         params = get_params_dialog(params, url_meta, dialog = dialog)
     # then the student's ID (and password if neccessarry)
     fetch_params_meta = {
-            'username':{'descriptions': {'si': u'Uporabniško ime', 'en': u'Username'}, },
+            'username':{'descriptions': {'si': 'Uporabniško ime', 'en': 'Username'}, },
     }
     if params['task_url'] is not None and (
             params['task_url'].startswith('http')):
@@ -120,7 +120,7 @@ def locate_task(params, argparser, dialog):
     argparser = add_meta_to_argparser(argparser, meta = fetch_params_meta, defaults = params)
     args, unknown_args = argparser.parse_known_args()
     # update params with the now known args
-    for k, v in fetch_params_meta.iteritems():
+    for k, v in fetch_params_meta.items():
         params[k] = vars(args).get(k, params.get(k, None))
     if dialog is not None:
         params = get_params_dialog(params, fetch_params_meta, dialog=dialog)
@@ -166,12 +166,12 @@ if __name__ == '__main__':
         task_name = params['task_name']
         if task_url.startswith('http'):
             http_auth(task_url, params['username'], params['password'])
-        print "fetching {task_url}/{task_name}/task.py".format(**params)
-        req = urllib2.Request("{task_url}/{task_name}/task.py".format(**params))
-        source = urllib2.urlopen(req)
+        print("fetching {task_url}/{task_name}/task.py".format(**params))
+        req = urllib.request.Request("{task_url}/{task_name}/task.py".format(**params))
+        source = urllib.request.urlopen(req)
         task, task_check, task_params_meta, gen_params = load_task(source)
     except Exception as e:
-        print params
+        print(params)
         print(e)
         if basic_args.help:
             argparser.print_help()
@@ -190,8 +190,8 @@ if __name__ == '__main__':
         task_params.update(gen_params(params['username'], task_params_meta))
         # print ("params after: {} {}".format(params, task_params))
     if task_url.startswith('http'):
-        req = urllib2.Request("{task_url}/{task_name}/params.json".format(**params))
-        web_task_params = json.load(urllib2.urlopen(req))
+        req = urllib.request.Request("{task_url}/{task_name}/params.json".format(**params))
+        web_task_params = json.load(urllib.request.urlopen(req))
         task_params.update(web_task_params)
     params_argparser = argparse.ArgumentParser(parents=[argparser], conflict_handler='resolve', add_help=True)
     params_argparser = add_meta_to_argparser(params_argparser, task_params_meta, defaults=task_params)
@@ -208,7 +208,7 @@ if __name__ == '__main__':
         exit(0)
     # run task.task()
     public_params = dict()
-    for k in inspect.getargs(task.func_code)[0]:
+    for k in inspect.getargs(task.__code__)[0]:
         public_params[k] = task_params[k]
     params['task_params'][params['task_name']] = task_params
     # save parameters for the next run
@@ -224,7 +224,7 @@ if __name__ == '__main__':
         exit(1)
     try:
         result, hints = task_check(task_result, task_params)
-        print result, hints
+        print(result, hints)
     except Exception as e:
         print("Error running task_check(results, params):")
         print(e)
diff --git a/kpov_judge/web/kpov_judge/kpov_draw_setup.py b/kpov_judge/web/kpov_judge/kpov_draw_setup.py
index 0042389..41f5e01 100644
--- a/kpov_judge/web/kpov_judge/kpov_draw_setup.py
+++ b/kpov_judge/web/kpov_judge/kpov_draw_setup.py
@@ -7,7 +7,7 @@ def draw_setup(computers, networks, destination=None,
         icon_suffix = format
     icon_suffix = '.' + icon_suffix
     G = pgv.AGraph(imagepath=icon_path + '/')
-    print G.graph_attr
+    print(G.graph_attr)
     have_internet = []
     for net in networks:
         net_name = net.get('name', 'net')
@@ -39,5 +39,5 @@ def draw_setup(computers, networks, destination=None,
 
 if __name__ == '__main__':
     import sample_task as task
-    print draw_setup(task.computers, task.networks)
+    print(draw_setup(task.computers, task.networks))
     
diff --git a/kpov_judge/web/kpov_judge/kpov_judge.py b/kpov_judge/web/kpov_judge/kpov_judge.py
index 2b1d3c6..1605089 100755
--- a/kpov_judge/web/kpov_judge/kpov_judge.py
+++ b/kpov_judge/web/kpov_judge/kpov_judge.py
@@ -85,7 +85,7 @@ def results_post(class_id, task_id, results):
         meta = {}
     else:
         meta = meta['params']
-    for param_name, param_meta in meta.iteritems():
+    for param_name, param_meta in meta.items():
         if param_meta.get('w', False) and param_name in user_params:
             params[param_name] = user_params[param_name]
     try:
@@ -151,7 +151,7 @@ def public_meta(db, class_id, task_id):
     shown = {}
     try:
         meta = db.task_params_meta.find_one({'class_id': class_id, 'task_id': task_id})['params']
-        for k, v in meta.iteritems():
+        for k, v in meta.items():
             try:
                 if v['public']:
                     shown[k] = v
@@ -239,14 +239,14 @@ def task_greeting(class_id, task_id, lang):
         instructions = instructions.get(lang, instructions[app.config['DEFAULT_LANG']])
     except Exception:
         try:
-            instructions = instructions.values()[0]
+            instructions = list(instructions.values())[0]
         except Exception as e:
             instructions = str(e)
             instr_ok = False
     if instr_ok:
         try:
             public_params = {}
-            for k, v in meta.iteritems():
+            for k, v in meta.items():
                 if v.get('public', False):
                     public_params[k] = params.get(k, "???")
             # instructions = instructions.format(**public_params).decode('utf8')
@@ -280,14 +280,14 @@ def params_json(class_id, task_id):
             new_params = json.loads(flask.app.request.form['params'])
         except Exception:
             new_params = {}
-        for name in params.iteritems():
+        for name in params.items():
             if meta.get(name, {'w': False}).get('w', False) and k in new_params:
                 params[name] = new_params[name]
             if meta.get(name, {'public': False})['public']:
                 shown_params[name] = params[name]
         db.task_params.update({'class_id': class_id, 'task_id': task_id, 'student_id': student_id}, {'$set': {'params': params}})
     else:
-        for name, param in params.iteritems():
+        for name, param in params.items():
             if meta.get(name, {'public': False})['public']:
                 shown_params[name] = param
     return json.dumps(shown_params)
@@ -299,13 +299,13 @@ def params_html(class_id, task_id, lang):
     db = g.db
     params, meta = get_params(class_id, task_id, student_id, db)
     shown_params = {}
-    for name, meta_param in meta.iteritems():
+    for name, meta_param in meta.items():
         if meta_param.get('public', False):
             shown_params[name] = params.get(name, '')
     if flask.app.request.method == 'POST':
         form = flask.app.request.form
         new_params = {}
-        for k, v in meta.iteritems():
+        for k, v in meta.items():
             if v.get('w', False):
                 params[k] = flask.app.request.form[k]
             if v.get('public', False):