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How to Read Manual Pages in Linux | man Command

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The “man” command, short for manual, is a powerful tool in the Linux operating system that allows users to access detailed information about various commands, utilities, and system calls. The “man” command provides comprehensive documentation, helping users understand how to use and configure different elements of the Linux environment. This article will explore the “man” command in detail, covering its syntax, options, and providing practical examples.

Syntax of the “man” Command:

The basic syntax of the “man” command is as follows:

man [option] [command]

Here,

option” refers to additional flags that modify the behavior of the “man” command,

command” is the Linux command or utility for which you want to access the manual.

Accessing Manual Pages:

To access the manual page for a specific command, simply type:

man [command]

For example, to view the manual for the “ls” command, you would enter:

man ls

This will display detailed information about the “ls” command, including its usage, options, and examples.

Once you’ve accessed a manual page, you can navigate through it using various commands. The common navigation keys include:

  • Spacebar: Move forward one page.
  • Enter: Move forward one line.
  • B: Move backward one page.
  • Q: Quit the manual viewer.

Sections in Manual Pages:

Manual pages are organized into different sections, each serving a specific purpose. The primary sections include:

  • NAME: Provides the name and a brief description of the command.
  • SYNOPSIS: Describes the syntax of the command.
  • DESCRIPTION: Offers a detailed explanation of the command’s functionality.
  • OPTIONS: Lists the available command-line options and their descriptions.
  • EXAMPLES: Provides practical examples demonstrating command usage.
  • SEE ALSO: Suggests related commands or resources.

Every manual is divided into the following sections:

  • Executable programs or shell commands
  • System calls (functions provided by the kernel)
  • Library calls (functions within program libraries
  • Games
  • Special files (usually found in /dev)
  • File formats and conventions eg /etc/passwd
  • Miscellaneous (including macro packages and conventions), e.g. groff(7)
  • System administration commands (usually only for root)
  • Kernel routines [Non standard]

Exploring Command Options

The “man” command itself has options that enhance its functionality:

Option

Description

man [command]

Display the manual page for the specified command.

-f, –whatis

Display a concise one-line description of the command.

-k, –apropos

Search for commands related to a given keyword.

-a, –all

Display all matching manual pages for the specified command.

Spacebar

Move forward one page in the manual.

Enter

Move forward one line in the manual.

B

Move backward one page in the manual.

Q

Quit the manual viewer.

1. Section-num in man Command in Linux

Since a manual is divided into multiple sections so this option is used to display only a specific section of a manual.

Syntax :

man [SECTION-NUM] [COMMAND NAME]

Example:

man 2 intro

Output:

In this example, the manual pages of command ‘intro‘ are returned which lies in the section 2.

2. -f option in man Command in Linux

One may not be able to remember the sections in which a command is present. So this option gives the section in which the given command is present.

Syntax:

man -f [COMMAND NAME]

Example:

man -f ls

Output:

In this example, the command ‘ls‘ is returned with its section number.

3. -a option in man Command in Linux

This option helps us to display all the available intro manual pages in succession.

Syntax:

man -a [COMMAND NAME]

Example:

man -a intro

Output:

In this example you can move through the manual pages(sections) i.e either reading(by pressing Enter) or skipping(by pressing ctrl+D) or exiting(by pressing ctrl+C).

4. -k option in man Command in Linux

This option searches the given command as a regular expression in all the manuals and it returns the manual pages with the section number in which it is found.

Syntax:

man -k [COMMAND NAME]

Example:

man -k cd

Output:

The command ‘cd‘ is searched in all the manual pages by considering it as a regular expression.

5. -w option in man Command in Linux

This option returns the location in which the manual page of a given command is present.

Syntax:

man -w [COMMAND NAME]

Example:

man -w ls

Output:

The location of command ‘ls‘ is returned.

6. -I option in man Command in Linux

It considers the command as case sensitive.

Syntax:

man -I [COMMAND NAME]

Example:

man -I printf

Output:

The command ‘printf’ is taken as case-sensitive i.e ‘printf’ returns the manual pages but ‘Printf’ gives error.

How to Read Manual Pages in Linux | man Command – FAQs

How to view the Manual for “cd” Command Using man Command?

man cd

This command will display the manual page for the “cd” command, including information about its options, syntax, and examples.

How to Searching for Commands Related to “file” Using man Command?

man -k file

This command will provide a list of commands related to the keyword “file,” helping users discover relevant utilities.

How to Display a One-Line Description of “ls” Using man Command?

man -f ls

This command will present a brief one-line description of the “ls” command, useful for quick reference.

Are there any alternative ways to read man pages?

Yes, there are a few alternative tools you can use:

  • man2html: Converts man pages to HTML format, which can be easier to read on a graphical user interface (GUI).
  • tldr: Provides shorter, simplified versions of man pages.
  • whatis: Gives a very brief one-line summary of a command.

I can’t find the man page for a specific command, what do I do?

There are a few possibilities:

  • The command might not have a man page. Some smaller or less common commands might lack documentation.
  • You might have misspelled the command name. Double-check your spelling and try again.
  • The man page might be located in a different section. You can use the -k option with man to search for keywords across all sections. For example, `man -k ls` will search for all man pages mentioning “ls”.

How to Search Manual Pages in Linux?

There are three main ways:

  1. Using the `man` command: This is the classic approach. Type `man` followed by the command name to find its manual page. For example, `man mkdir` will show you the manual page for the `mkdir` command.
  2. Using the `-k` option: Want to search for keywords across all manual pages? Use man -k followed by your keyword(s). For instance, `man -k permissions` will find pages mentioning “permissions“.
  3. Using the `apropos` command: Similar to `man -k`, but `apropos` also searches descriptions, not just names. Try `apropos networking` to find pages related to networking.

Conclusion

In this article we discussed the “man” command in Linux which is an essential tool for accessing detailed documentation on commands, utilities, and system calls. It provides a comprehensive guide with organized sections, including syntax, options, and examples. With options like -f, -k, and -a, users can quickly retrieve concise descriptions, search related commands, and access all matching manual pages. Navigating through manual pages is simplified with common keys like Spacebar and Enter. The “man” command is not just a documentation tool; it is a valuable resource for users of all levels, contributing to a better understanding of Linux commands and enhancing command-line proficiency.

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Last Updated : 24 Jan, 2024
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