Table of Contents
This article will guide you to use the man command to display a program’s manual page.
Most programs executed in Linux include a section called manual or man page.
What is a man page?
Man page is understood as a document describing program execution information, executable programs herein can be understood as Linux commands.
The man page displays information in the terminal window and follows the format of the less command.
That is, you view the man page content in a separate window and use the arrow keys to turn the page.
Or if you use a terminal on a Linux desktop, you can scroll the mouse pointer to forward the information page in the man page.
The page usually includes title information, syntax structure, purpose of the command, options of the command and description of options.
Note: man page only includes descriptive information about the program, not including tutorials or examples.
Use the man command to display the man page
The syntax of man command is quite simple:
$ man programWith the program is the name of the command you want to see.
For example, I will display the man page of the mkdir command, type:
$ man mkdir
Note: to quit the man page, press the q key on your keyboard.
Man page organiztion
The man page is divided into different sections and numbered. This is also useful in case you want to see a section in the program documentation.
The following table will list all the sections of the man page.
| Section | Contents |
| 1 | Executable programs or shell commands |
| 2 | System calls (functions provided by the kernel) |
| 3 | Library calls (functions within program libraries) |
| 4 | Special files (usually found in /dev) |
| 5 | File formats and conventions eg /etc/passwd |
| 6 | Games |
| 7 | Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7) |
| 8 | System administration commands (usually only for root) |
| 9 | Kernel routines [Non standard] |
To see more information about the man page sections, you can read this link or type the command below.
$ man manNotice that DESCRIPTION will have the content like this.
DESCRIPTION
man is the system's manual pager. Each page argument given to man is normally the name of a
program, utility or function. The manual page associated with each of these arguments is then
found and displayed. A section, if provided, will direct man to look only in that section of
the manual. The default action is to search in all of the available sections following a pre-
defined order ("1 n l 8 3 2 3posix 3pm 3perl 5 4 9 6 7" by default, unless overridden by the
SECTION directive in /etc/manpath.config), and to show only the first page found, even if page
exists in several sections.
The table below shows the section numbers of the manual followed by the types of pages they
contain.
1 Executable programs or shell commands
2 System calls (functions provided by the kernel)
3 Library calls (functions within program libraries)
4 Special files (usually found in /dev)
5 File formats and conventions eg /etc/passwd
6 Games
7 Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
8 System administration commands (usually only for root)
9 Kernel routines [Non standard]
A manual page consists of several sectionsNow try some examples with the section in the man page. I will see the documentation for the passwd command.
$ man 1 passwd
$ man 2 passwd
No manual entry for passwd in section 2
See 'man 7 undocumented' for help when manual pages are not available.
$ man 3 passwd
No manual entry for passwd in section 3
See 'man 7 undocumented' for help when manual pages are not available.
$ man 4 passwd
No manual entry for passwd in section 4
See 'man 7 undocumented' for help when manual pages are not available.
$ man 5 passwd
$ man 6 passwd
No manual entry for passwd in section 6
See 'man 7 undocumented' for help when manual pages are not available.
$ man 7 passwd
No manual entry for passwd in section 7
See 'man 7 undocumented' for help when manual pages are not available.
$ man 8 passwd
No manual entry for passwd in section 8
See 'man 7 undocumented' for help when manual pages are not available.
$ man 9 passwd
No manual entry for passwd in section 9
See 'man 7 undocumented' for help when manual pages are not available.As you can see from the above results, the passwd command only has 3 sections of 1, 2 and 5. Therefore, not all man pages of the programs have all 9 sections.
Conclusion
By using the man command, you can display the content of the man page. It will give you a lot of information about the command or program you are trying to know.
From definitions, goals, abbreviations of commands, options, and so on.
(This is an article from my old blog that has been inactive for a long time, I don’t want to throw it away so I will keep it and hope it helps someone).
