Organization of files

The file system is made up of a set of regular files, special files, symbolic links, and directories. These components provide a way to organize, retrieve, and manage information electronically. ``File and device input/output'' introduced some of the properties of directories and files; this section will review them briefly before discussing how to use them.

• A regular file is a collection of characters stored on a disk. It may contain text for a report or code for a program.

• A special file represents a physical device, such as a terminal or disk.

• A symbolic link is a file that points to another file.

• A directory is a collection of files and other directories (sometimes called subdirectories). Use directories to group files together on the basis of any criteria you choose. For example, you might create a directory for each product that your company sells or for each of your student's records.

The set of all the directories and files is organized into a tree shaped structure. ``A sample file system'' shows a sample file structure with a directory called root (/) as its source. By moving down the branches extending from root, you can reach several other major system directories. By branching down from these, you can, in turn, reach all the directories and files in the file system.

A sample file system

In this hierarchy, files and directories that are subordinate to a directory have what is called a parent/child relationship. This type of relationship is possible for many layers of files and directories. In fact, there is no limit to the number of files and directories you may create in any directory that you own. Neither is there a limit to the number of layers of directories that you may create. Thus, you have
the capability to organize your files in a variety of ways, as shown in the preceding figure.