...
s2s_${centre}_${version}_${stream}_${yyyy}${mm}${dd}${cyclehh}_${levelType}_${ensembleMember}.grib2
centre: eccodes/mars acronym as per https://apps.ecmwf.int/codes/grib/format/mars/centre/
version: test/prod
stream: enfo/enfh for real-time/reforecast outputsversion: test/prod
levelType: pl/sl/pt/pt/oc for pressure/surface/potential temp/potential vorticity/ocean level
ensembleMember: 000, 001, 002.... (000 for control forecast, 001 for the 1st epsmenber etc)
example (UKMO): s2s_ukmoegrr_prod_enfo_2019101000_pl_002.grib2
...