4 File – What is .4 file and how to open it?

Unix Section 4 Manual Page (4 File)

Unix Section 4 Manual Page (4 file) is a plain text file format used in Unix-like operating systems to provide documentation for system calls, kernel interfaces, and special files. These man pages are particularly designed for C and shell programmers, adhering to the well-established Unix man page conventions.

4 files typically contain detailed information about the function, usage, arguments, error codes, and examples of the documented subject. They are structured into several sections, each starting with a specific header and providing a particular type of information. The sections include the name, synopsis, description, options, environment, return values, and examples. These man pages are considered invaluable resources for developers and system administrators working with Unix systems, providing comprehensive and standardized documentation for various system components.

Opening a .4 File

A .4 file is a text file that contains a manual page for a Unix program. Manual pages are a form of documentation that provide instructions on how to use a particular program. They are typically organized into sections, with each section covering a specific aspect of the program.

To open a .4 file, you can use a text editor or a man page viewer. Text editors such as Notepad or TextEdit can be used to view the raw text of the .4 file. Man page viewers are programs that are specifically designed to display manual pages. They typically include features such as search, navigation, and formatting.

Using a Man Page Viewer

One of the most common man page viewers is called man. It is available on most Unix systems. To use man, simply enter the following command at the terminal:


man <program name>


For example, to view the manual page for the ls command, you would enter the following command:


man ls


This will display the manual page for the ls command in a pager program. You can use the arrow keys to navigate through the manual page and the q key to quit.

File Format and Usage

A file with the .4 extension is a Unix Section 4 Manual Page. It contains formatted text that describes the syntax and usage of a particular command, utility, or function in a Unix-like operating system. .4 files are typically located in the /usr/share/man/man4 or /usr/local/share/man/man4 directories.

To view the contents of a .4 file, users can use the “man” command followed by the name of the command or function they wish to learn about. For example, to view the manual page for the “ls” command, users would enter “man ls” into their terminal. .4 files are typically divided into several sections, including the name, synopsis, description, options, and examples. The name section identifies the command or function and provides a brief overview of its purpose. The synopsis section provides the syntax for the command or function, including the required and optional arguments. The description section provides a detailed explanation of the command or function’s functionality. The options section lists the available options for the command or function and describes their effects. Finally, the examples section provides examples of how to use the command or function.

History and Development

Unix Section 4 Manual Pages have been a part of the Unix operating system since its early days. The first manual pages were written by Dennis Ritchie and Ken Thompson in the early 1970s. The .4 extension was chosen to denote manual pages that describe functions (as opposed to commands or utilities, which are described in .1 files). Over time, the format of manual pages has evolved to include more detailed information and more consistent formatting. However, the basic structure and purpose of manual pages has remained largely unchanged. Today, .4 files are an essential resource for Unix users and system administrators, providing quick and easy access to information about the commands and functions available on their systems.

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