In the Linux operating system, all files and directories are organized into a root "/" beginning of an inverted tree
The top level of the file system is the root of the beginning, the system uses "/" to represent the root directory under the root directory of either directory or file, and each directory and can contain (sub) directory or file. And so forth can constitute a large file system.
Note that the directory or file names are case-sensitive, such as dog, DOG Dog and three different directories or files. Complete directory or file path is a series of directory names composed, each directory separated by a "/." The cat was complete path / home / cat.
In the file system, there are two special directory, a directory where the user is working, that the current directory, can represent a point. ""; The other is the parent directory of the current directory, also known as the parent directory, with two points ".." indicates.