In this video, you'll learn about man.
Man is the essential way to get help about your system.
Now, there's an important thing that you should realize, and that is that in the RHCSA exam,
there's no internet access.
For that reason, man is the best source to get extensive usage information from your
system.
In man, there are sections that define the different command types, and many man pages
have examples.
Search for information in man pages using forward slash, and other solutions for documentation
might be available, but not as important on the RHCSA exam.
For instance, GNU software has full documentation available through info, and pinfo is available
as an easier interface to navigate than info.
But focus on man.
Man is really all that matters.
So documentation in man is organized in different sections, and when you work with man, it makes
sense to know a bit about these sections.
For basic administration, the following sections matter most.
Section one, which is executable programs or shell commands.
Section five, which is file formats and conventions.
And section eight, which is system administration commands.
You can find more information about these sections using man man, and use man section
number intro to get an introduction to the topic of a specific section number.
Let me show you.
So let's start with man man, where we have an overview of the man page.
Now in this overview of the man page, it always starts with the name of the command, which
is funnily enough written in uppercase.
Just ignore that.
It's just a headline, and in headlines, it's common to write it in uppercase.
You can also see the section that the command is coming from.
Then we have the name with a short explanation, and the synopsis is giving information about
different ways to use the command.
There's a couple of elements that we should discuss in this synopsis.
First, the man option is between square brackets.
If it's between square brackets, that means that it is optional.
You may use it.
You don't have to use it.
Then we see this construction page, dot, dot, dot.
Page is a placeholder, and the man page is trying to indicate that by putting a line
under page, and the dot, dot, dot means that you can repeat the previous item multiple
times.
So you can do man on one page or on multiple pages.
And then we have specific use cases like man minus K, minus uppercase K, minus F, and so
on.
Then, and that's also a common element that you will always find in man pages, there's
the description.
And in the description, in this case, you have the list of all the sections.
Believe me, for now, only section 1 and 5 and 8 do matter.
So 1 is for commands that are usable by end users, 5 is for configuration files, and 8
is for commands that require pseudo-privileges, system administrator privileges.
Now a little bit more about navigation.
In a man page, you can use a space bar to navigate down.
You can also use uppercase G to go all the way down.
I like going all the way down because if you go all the way down, then you see a list of
related man pages.
It's not always completely to the point, but it may give you interesting help telling you
about related commands.
You might be in a man page for a command that is just not the man page that you are looking
for, and then you should be interested in these related commands.
Also convenient is that when I use man on a more complex command, let me use man on
SEManageFContext, for instance, I'll tell you later what it is.
For now, that doesn't matter.
What matters is that if you use uppercase G, you can see examples.
If I have one advice for you, particularly when the topics are becoming more complex,
always have a look and see if there is usable examples because these examples might help
you to get through topics on the exam.
And last but not least, man 8 intro.
You can do this for any section number.
All of these sections have an intro page.
Now the intro for section 8 is not very interesting, but if ever you are wondering what are
system calls, well, man 2 intro is giving an introduction into system calls, which happens
to be a very important part of the Linux operating system.
So if you're in for a good read, have a look at those.