diff --git a/configure.py b/configure.py
index cdedd88..7fba0c1 100755
--- a/configure.py
+++ b/configure.py
@@ -26,7 +26,8 @@ d_default = {
   "FCFLAGS" : '-O2',
   "RANLIB" : 'ranlib',
   "AR" : 'ar',
-  "BUILD_SYSTEM" : 'make'
+  "BUILD_SYSTEM" : 'make',
+  "NINJA" : 'ninja',
 }
 
 CONFIG_FILES=' '.join([ os.path.join("config",x) for x in os.listdir('config') if x != '.empty'])
diff --git a/src/Makefile b/src/Makefile
index 66cdeb5..c5bb04e 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -52,10 +52,10 @@ static: ../lib/libezfio.a ../lib/libezfio_irp.a
 	cp ../lib/libezfio.a ../lib/libezfio_irp.a
 
 ../Python/ezfio.py: ../lib/libezfio.a
-	python create_python.py
+	python2 create_python.py
 
 ../Ocaml/ezfio.ml: ../lib/libezfio.a
-	python create_ocaml.py
+	python2 create_ocaml.py
 
 IRPF90_temp/irpf90.a: $(BUILD_FILE)
 	$(call run_and_touch, $<, $@)
diff --git a/src/libezfio_file.irp.f b/src/libezfio_file.irp.f
index 9334a2a..a9384ce 100644
--- a/src/libezfio_file.irp.f
+++ b/src/libezfio_file.irp.f
@@ -159,7 +159,7 @@ subroutine ezfio_set_file(filename_in)
     call ezfio_mkdir(trim(libezfio_filename)//'/ezfio')
     call system('LANG= date > '//trim(libezfio_filename)//'/ezfio/creation')
     call system('echo $USER > '//trim(libezfio_filename)//'/ezfio/user')
-    BEGIN_SHELL [ /usr/bin/python ]
+    BEGIN_SHELL [ /usr/bin/env python2 ]
 import os
 command = "'echo %s > '//trim(libezfio_filename)//'/ezfio/library'"
 cwd = os.getcwd()
@@ -178,7 +178,7 @@ subroutine ezfio_finish()
 ! Close all open buffers
  END_DOC
  close(libezfio_iunit)
- BEGIN_SHELL [ /usr/bin/python ]
+ BEGIN_SHELL [ /usr/bin/env python2 ]
 import os
 from zlib import crc32
 print '  call irp_finalize_%s'%(str(abs(crc32(os.getcwd()))))
diff --git a/src/libezfio_groups.irp.f b/src/libezfio_groups.irp.f
index 8b1d991..9bcc9ab 100644
--- a/src/libezfio_groups.irp.f
+++ b/src/libezfio_groups.irp.f
@@ -22,7 +22,7 @@
 !   31062 Toulouse Cedex 4      
 !   scemama@irsamc.ups-tlse.fr
 
-BEGIN_SHELL [ /usr/bin/python ]
+BEGIN_SHELL [ /usr/bin/env python2 ]
 import groups
 END_SHELL
 
diff --git a/src/libezfio_util.irp.f b/src/libezfio_util.irp.f
index 1ab88b4..b7a0c6f 100644
--- a/src/libezfio_util.irp.f
+++ b/src/libezfio_util.irp.f
@@ -114,7 +114,7 @@ subroutine libezfio_closez(filename,mode)
 end
 
 
-BEGIN_SHELL [ /usr/bin/python ]
+BEGIN_SHELL [ /usr/bin/env python2 ]
 from f_types import format, t_short