code: func (m *ModuleSpec) Set(value string) error {
  	var filter []modulePat
  	for _, pat := range strings.Split(value, ",") {
  		pattern, v, err := parseFilter(pat)
  		if err != nil {
  			return err
  		}
  		if v == 0 {
  			continue
  		}
  		// TODO: check syntax of filter?
  		filter = append(filter, modulePat{pattern, isLiteralGlob(pattern), Level(v)})
  	}
  	m.filter = filter
  	return nil
  }
docs: // Syntax: recordio=2,file=1,gfs*=3