cmsDriver.py is a tool in CMSSW that is used to create workflows for sample generation. Its syntax and usage are explained in the following TWiki pages:

• https://twiki.cern.ch/twiki/bin/view/CMSPublic/SWGuideCmsDriver
• https://twiki.cern.ch/twiki/bin/view/CMSPublic/SWGuideCmsDriverEras
• https://twiki.cern.ch/twiki/bin/view/CMSPublic/WorkBookGenIntro

The implementation of the script is in $CMSSW_RELEASE_BASE/src/Configuration/Applications/python/ConfigBuilder.py.