CDO

Hello, I have around 7000 netcdf4 files. All of the them do not have time axis. i want to write a shell script which can automatically assign the time axis to the netcdf4 data. my netcdf4 data starts from 1970-01-01,00:00:00,1day.

Any help to write a shell script that can add the time axis will be appreciated. i already tried merge, cat and copy, but the it brings uncertainties in the output data. Thanks