diff --git a/docker/tools/onlbuilder b/docker/tools/onlbuilder
index be1bc15b1..eabe38f02 100755
--- a/docker/tools/onlbuilder
+++ b/docker/tools/onlbuilder
@@ -1,4 +1,4 @@
-#!/usr/bin/python2
+#!/usr/bin/env python3
 
 import os
 import sys
@@ -126,10 +126,10 @@ logger.debug('arguments: %s\n' % vars(ops))
 
 if ops.pull:
    try:
-      print "Pulling %s..." % ops.image
+      print("Pulling %s..." % ops.image)
       x = subprocess.check_output(('docker', 'pull', ops.image), stderr=subprocess.STDOUT)
-      print "done."
-   except subprocess.CalledProcessError, e:
+      print("done.")
+   except subprocess.CalledProcessError as e:
       sys.stderr.write("** Failed to pull the docker image %s (%d):\n\n%s\n" % (ops.image, e.returncode, e.output))
       sys.exit(1)
 
@@ -174,7 +174,7 @@ else:
    g_docker_arguments = "docker run --privileged %(interactive)s -t -e DOCKER_IMAGE=%(image)s  --name %(name)s %(ssh_options)s %(volume_options)s  " % g_arg_d
 
    if ops.isolate is not None:
-      if len(ops.isolate) is 0:
+      if len(ops.isolate) == 0:
          ops.isolate.append(os.getcwd())
 
       isolates = [ os.path.abspath(i) for i in ops.isolate ]