Collections of files are stored in directories. These collections of files are often related to each other, and storing them in a structure of directories keeps them organized. There are many ways to create, use, and manipulate files. All file types recognized by the system fall into one of these categories. However, the operating system uses many variations of these basic types.
Regular files are the most common.
When a word processing program is used to create a document, both the program and the document are contained in regular files. Regular files contain either text or binary information. Text files are readable by the user. Binary files are readable by the computer. Binary files can be executable files that instruct the system to accomplish a job.