Linux operating system commands help

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Title: Linux operating system help command
time: March 20, 2019
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in learning Linux operating system, you may often encounter some ordered his never seen before, so we need to learn command usage.
In order to learn the easiest way is to use the help command.

Below us to understand what we can do to help approaches rely on? Of course, for different commands may also help very much the same.
One way: take command help help.
Method two: View through the man command help manual.
The third method: View command assistance through official manual.
Method four: View command assistance through baidu, Google and other search engines.

1. help command help
help command help command due to different sources, view the help of way will be different. For example: in the command key and foreign key command help will be different.
Of course, there are some other reasons to see a way to help produce transformation. The following is a common query help focus the way.
[root @ mysql1 ~] # the setfacl --help
[root @ mysql1 ~] # Help cd
[root @ mysql1 ~] # RAR Help
There is also a helpful way to see -h, such an order is not common here for example we will not give up.

2. man command help
help help help only have access to simple commands, but you can see the man page look more advanced usage and the use of examples.
man manual eight chapters, specific sections are as follows:
[the root mysql1 @ ~] # man man
. 1 the Commands the User
2 the System Calls
. 3 C Library Functions
. 4 Special Devices and Files
. 5 File Formats and Conventions
. Games et. 6 of Al.
. 7 Miscellanea
. 8 system Administration tools and deamons
as system operation and maintenance staff could use to 1,2,3,5 and 8 and other chapters.
This can be divided into five chapters help command (Chapter 1, Section 8), file format (Chapter 5), to help function (Chapter 2, Section 3).

After understanding these contents, we learn some common uses:
[root @ mysql1 ~] # man the setfacl
[root @ mysql1 ~] # man passwd // 1 in accordance with section view user help manual
[root @ mysql1 ~] # man -a passwd // check out all the chapters related to the passwd

3. official Guide command help
in fact, under normal circumstances, you can basically solve the problem by helping the first two.
If you have two ways to help and man pages also can not solve the problem can be solved through the official manual.
However, this approach may be more complicated, in general, it is recommended to find help through baidu, Google and other search engines.
Official Handbook:
http://docs.redhat.com redhat(5/6/7)
http://www.mysql.com docs