create file list

 eos ls /eos/cms/store/group/comm_ecal/localreco/cmssw_720p4_zeromaterial/photongun_nopu | awk '{print "'\''/store/group/comm_ecal/localreco/cmssw_720p4_zeromaterial/photongun_nopu/"$1"'\'',"}' > files.py

editare files.py per scrivere files=

nel _cfg.py

from  files import filenames
fileNames = cms.untracked.vstring(filenames)