intro Command in Linux
The intro in Linux refers to a set of introductory manual pages found in each section of the system's manual, also known as man pages. These pages, titled intro, are not standalone commands but are accessed through the man command. Each intro page provides an overview of its respective sections.
Table of Contents
Here is a comprehensive guide to the options available with the intro command −
- Syntax of Accessing intro Manual Pages
- Contents of intro Manual Pages
- Navigating intro Manual Pages
- Accessing intro Manual Pages
Syntax of Accessing intro Manual Pages
There are a total of eight (8) introductory manual pages that can be accessed using the man command. Each manual gives a detailed introduction to Linux commands, file systems, system calls, and other miscellaneous information.
The general syntax of accessing the intro is as follows −
man N intro
In the above syntax, man is the command to access manual pages of any command. N is used to specify the intro man page number from 1 to 8.
Contents of intro Manual Pages
The contents of each intro manual page are listed below −
| Sections | Description |
|---|---|
| Section 1 | User commands and tools for general tasks |
| Section 2 | System calls provided by the Linux kernel |
| Section 3 | Library functions for programming |
| Section 4 | Special files (device files) and drivers |
| Section 5 | File formats and configuration file syntax |
| Section 6 | Games and entertainment programs |
| Section 7 | Miscellaneous topics such as conventions and standards |
| Section 8 | System administration commands and tools |
Navigating intro Manual Pages
To navigate the intro manual page, press the up and down directional keys on the keyboard. The / is used to search for a pattern and the n key moves to the next match. To get detailed help with manual page navigation, press the h key −
It opens a guide page that provides shortcut keys and commands to navigate the page, search specific parts, and jump to a specific part of the page. To quit the manual page, press q.
Accessing intro Manual Pages
This section shows how to use the man command to access various introductory manual pages −
Section 1 − To access the first section of the intro manual page, use the following command −
man 1 intro
Or it can simply be accessed without specifying the number −
man intro
Section 1 introduces basic user commands, including file manipulation tools, shells, and editors, providing an overview of commonly used commands such as ls, cp, mv, rm, and grep. It explains their function, syntax, and usage, along with concepts like exit status, pathnames, and file hierarchy. Key commands like pwd, cd, mkdir, find, mount, ps, and kill are covered, focusing on tasks such as navigating directories, managing files, and handling processes.
Section 2 − To access the second section of the intro manual page, use the following command −
man 2 intro
Section 2 covers Linux system calls, which are accessed via C library wrappers. These wrappers handle argument passing, kernel invocation, and error processing. On success, most system calls return 0, while errors return a negative number. Some calls may require feature test macros.
Section 3 − To access the third section of the intro manual page, use the command given below −
man 3 intro
This section covers library functions, mainly from the C standard library (libc), with some from other libraries such as libm and librt. It details linker options, feature test macros, and is organized into subsections for clear API design.
Section 4 − This section can be accessed using the following command −
man 4 intro
Section 4 describes special files, specifically device files located in /dev/*.
Section 5 − This section can be accessed using the following command −
man 5 intro
It describes file formats and corresponding C structures, along with documentation for various filesystems.
Section 6 − This section can be accessed using the following command −
man 6 intro
It describes games and other entertainment software available on the system.
Section 7 − The seventh section can be accessed using the following command −
man 7 intro
It provides miscellaneous information, including conventions, protocols, character set standards, and the standard filesystem layout.
Section 8 − This section can be accessed using the following command −
man 8 intro
It describes commands used by the superuser, such as system administration commands, daemons, and hardware-related commands.
Note − The intro pages often reference other related manual pages for more details.
Conclusion
The intro manual pages in Linux provide overviews for each of the eight manual sections, covering topics like user commands, system calls, library functions, file formats, and administrative tools. These pages provide a quick overview of Linux features and can be accessed with the man N intro command, where N is a number from 1 to 8.
In this tutorial, we explained the usage of the man command to access intro manual pages in Linux.