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The UNIX File System

While the Thunar file manager does a good job at abstracting the details of the underlying file system so the user does not need to care about them, it is sometimes useful to understand the basic concepts to get the whole picture. This section tries to give a brief introduction to the concepts of the UNIX file system, which is used today by all incarnations of UNIX, including Linux.

Folders and Paths

In a UNIX file system, all folders are arranged in a simple inverted tree structure descending and branching down from a single top-level folder which is called the root directory (the term directory is often used instead of folder) and displayed as File System in Thunar. This means that you can get from any folder to any other by going up the tree until you reach a common point, then down the tree through the appropriate subfolders until you reach your target.

The position of any file or folder in the tree can be described by its path. The path is the list of folders you would have to descend through to get to the target folder or file, starting from the top-level folder. For example /home/luke is the subfolder luke of the subfolder home of the top-level folder, and /home/luke/myfile.txt is the file myfile.txt in that subfolder. The leading / in these paths represents the top-level folder.

Every user has his or her own folder to hold personal files and settings. This folder is called the home directory and is displayed in Thunar as a special icon with the user's login name. The folder is similar to the My Files folder in Windows. The home directories of the various users in a system are usually located below the /home folder. For example /home/luke would be the home directory of the user with the login name luke, while /home/jane would be the home directory for the user with the login name jane.

File Types

You may have already heard that everything in UNIX is a file. This is true for most objects present in UNIX systems today. In fact, even devices are represented as special files. While this may not make sense at first sight, it is one of the strengths of UNIX and its derivatives and has helped it to maintain a simple core over the years where other operating systems had to introduce new concepts for every new technology.

These are the four most important types of files in the UNIX file system: