import netCDF4
from datetime import datetime
import glob
import os

folder="/work/mh0731/m300382/test_nwp_new/"
#
in_files="iefff0???0000_2_lbc.nc"
#
out_prefix="iefff_"

for filename in sorted(glob.glob(folder+in_files)):
    nc_temp = netCDF4.Dataset(filename)
    dtime = netCDF4.num2date(nc_temp.variables['time'][:], nc_temp.variables['time'].units)
    date_string = datetime.strftime(dtime[0], format='%Y%m%d%H')
    print('old = '+filename)
    print('new = '+folder+out_prefix+date_string+"_lbc.nc")
    os.rename(filename, folder+out_prefix+date_string+"_lbc.nc")