code: func (c *Context) FlagNames() (names []string) {
  	for _, flag := range c.Command.Flags {
  		name := strings.Split(flag.GetName(), ",")[0]
  		if name == "help" {
  			continue
  		}
  		names = append(names, name)
  	}
  	return
  }
docs: // FlagNames returns a slice of flag names used in this context.