介绍了Linux 下的文件类型和权限控制，Linux 下对所有的文件和目录都有一个访问权限，这些权限决定了谁能访问和如何访问这些

文件和目录。-Introduces Linux file types and under the authority control, Linux under all file and directory has an access permissions that determine who can access and how to access these files and directories.