如何删除指定路径中的文件和目录？

Now I want to remove some files and directory in a appointed path. such as file extension is .png and directries are named as abc , In the appointed directory maybe have some subdirectory , how to get the array of the files and directories at the appointed? and then how to remove them? I found a method: NSArray *paths = NSSearchPathForDirectoriesInDomains (NSLibraryDirectory, NSUserDomainMask, YES);Now I want to remove some files and directory i