diff --git a/src/libezfio_util.irp.f b/src/libezfio_util.irp.f
index 358eb3b..dadc34b 100644
--- a/src/libezfio_util.irp.f
+++ b/src/libezfio_util.irp.f
@@ -94,6 +94,28 @@ subroutine libezfio_openz(filename,mode,err)
  endif
 end
 
+subroutine libezfio_reopenz_unformatted(filename,mode,err)
+ implicit none
+  BEGIN_DOC
+! Opens a compressed file
+  END_DOC
+ character*(*)                  :: filename, mode
+ character*(1024)               :: fifo
+ integer                        :: err
+ fifo = trim(filename)//'.'//trim(PID_str)
+ err=1
+ 
+ if (mode(1:1) == 'r') then
+   call ezfio_error(irp_here,'Mode '//trim(mode)//' is not implemented.')
+ else if (mode(1:1) == 'w') then
+   close(unit=libezfio_iunit)
+   open(unit=libezfio_iunit,file=trim(fifo),form='UNFORMATTED',action='WRITE',access='STREAM',position='APPEND')
+   err=0
+ else
+   call ezfio_error(irp_here,'Mode '//trim(mode)//' is not implemented.')
+ endif
+end
+
 subroutine libezfio_closez(filename,mode)
  implicit none
   BEGIN_DOC
@@ -220,7 +242,7 @@ subroutine ezfio_write_array_%(type_short)s(dir,fil,rank,dims,dim_max,dat)
   integer                        :: err
   integer                        :: i
   character*(1024)               :: l_filename(2)
-  character*(32), allocatable    :: buffer(:)
+  character*(25), allocatable    :: buffer(:)
   if (libezfio_read_only) then
     call ezfio_error(irp_here,'Read-only file.')
   endif
@@ -232,16 +254,19 @@ subroutine ezfio_write_array_%(type_short)s(dir,fil,rank,dims,dim_max,dat)
   if (err == 0) then
     write(libezfio_iunit,'(I3)') rank
     write(libezfio_iunit,'(30(I20,X))') dims(1:rank)
+    close(unit=libezfio_iunit)
     
     allocate (buffer(dim_max))
     !$OMP PARALLEL DO PRIVATE(i)
     do i=1,dim_max
-      write(buffer(i), %(fmt)s) dat(i)
+      write(buffer(i)(1:24), %(fmt)s) dat(i)
+      buffer(i)(25:25) = ACHAR(10)
     enddo
     !$OMP END PARALLEL DO
-    write(libezfio_iunit,'(A)') buffer(1:dim_max)
-    deallocate(buffer)
+    call libezfio_reopenz_unformatted(trim(l_filename(1)),'wb',err)
+    write(libezfio_iunit) buffer
     call libezfio_closez(trim(l_filename(1)),'w')
+    deallocate(buffer)
   endif
   call system( 'mv -f '//trim(l_filename(1))//' '//trim(l_filename(2)) )
 end