5. Command Manual Page (man page)
Contents
With the power of the man page command, we can see what parameters a command accepts and how to use each parameter corresponding to the command. In this way, we are more efficient when using commands.
Page Sections
Given the wide variety of commands, man solves the problem of command classification through section numbering.
1. User Commands
Section (1) is used to categorise user commands.
Such as the date command we used earlier:
man date result
2. System Calls
Section (2) is used to categorise system call functions in the libraries provided by the Linux kernel.
epoll_create function provided by Linux kernel
3. Library Functions
Section (3) is used to classify C language standard library functions.
printf function provided by standard C library
4. Devices
Section (4) is used to categorise devices in the /dev directory for Linux systems.
"zero", a special file located in /dev directory
5. Files
Section (5) is used to categorise the description of the Linux file format and covers the /proc file system.
/etc/os-release contains the current Linux's distribution info
6. Games
Section (6) has not been used yet, so there is no appropriate example to illustrate.
haven't seen the command related to this section yet
7. Overviews, Conventions, and Miscellaneous
Section (7) classifies some other conventional content.
Network API for C language
8. Superuser and System Administration Commands
Section (8) categorises commands used by superusers and administrators, and this section also contains a small number of GNU C language libraries.
Logical Volume Manager tools creates virtual block devices based on physical devices
SYNOPSIS - Options & Arguments Syntax
Required
Angle brackets(<>) means the option or argument in the brackets is required when using the related command.
Optional
Square brackets([]) means the option or argument in the brackets is an option when using the related command.
Repeatable
Ellipsis(…) means the option or argument can exist multiple times when using the related command, such as same_option1 same_option2 and so on.
Alternation
A pipe(|) means when using the related command, we must use one of the options or arguments listed around it, for example, option1|option2.
Grouping
Curly brackets({}) means the available arguments of an option when using the related command, for example, ｛param1,param2,param3｝.
Page Layout
Layout
The layout of man is to segment information of command in pure text.
NAME
The name of the command and a brief introduction.
SYNOPSIS
The usage syntax of the command is usually described here.
DESCRIPTION
The description usually describes what the command does, including the application scenario of the command. In general, command authors often describe commands very clearly and efficiently to avoid excessive and unnecessary inquiries.
OPTIONS
Available options for this command, which are typically listed in the synopsis.
FILES
The files associated with this command, most of which are configuration files.
BUGS
Known problems and vulnerabilities.
EXAMPLE
Common usage examples.
AUTHOR
Command’s author(s).
COPYRIGHT
Command’s copyright information.
SEE ALSO
Other commands or functions associated with the command.
Page Flipping
Backward Flipping - Page
We can press SPACE key to flip to the backward page.
Backward Flipping - Line
We can press ENTER key to flip to the backward line.
Forward Flipping - Page
We can press b key to flip to the forward page.
Forward Flipping - Line
We can press k key to flip to the forward line.
Page Searching
Press n key to find next one. Press N key to find previous one.
Search Backward
We can use /WORD to search backward.
Search Forward
We can use ?WORD to search forward.
Exit Page
We can press the q key to go back from man page to the interactive command line
References The Linux man-pages project, Linux man pages online, Man Page, Creating Your Own MAN Page Version 1.0
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Author Dong Chen
LastMod Wed Feb 6 2019