确定目录是Mac OS X终端中的捆绑包还是包？

I'd like to be able to determine if a directory such as a '.app' is considered to be a package or bundle from Finder's point of view on the command line. I don't think this would be difficult to do with a small shell program, but I'd rather not re-invent the wheel if I don't have to.I'd like to be able to determine if a directory