使用opendir、readdir、closedir等函数来操作目录，使用stat函数来获取文件信息。编写一个功能完整的实现Unix/Linux下ls命令的程序，并且该程序实现了-l（长格式）选项功能，并能在Unix/Linux环境下正确地运行。-Use opendir, readdir, close to operate functions such as directory, use the stat function to get file information. Write a full-featured implementation of programs Unix/Linux under the ls command, and the program implements the-l (long format) option function, and can run correctly under Unix/Linux environment.