code: def _move_update(sourcepath, destname):
      
      if sys.platform.startswith('linux'):
          return os.system("/bin/mv -fu '%s' '%s'" % (sourcepath, destname))
      else:
          return os.system("rsync -ua --remove-source-files '%s' '%s'" % (sourcepath, destname))
docs: Move source to dest only if source is newer.