All language subtitles for 10 - The Terminal & Linux Commands English

Okay, now that we had a quick overview

of Kali Linux, I want to spend some time talking

about the Linux terminal.

So you can access the terminal

through this application right here.

So if we click on that,

it'll open the terminal window for us.

And as you can see, all it is is a black screen

where you can type commands.

Now, the Linux terminal is actually very, very powerful

because it can be used to do anything

that you can think of really.

A lot of the applications in Linux

that have a graphical interface

were command prompt programs first

and then people made a graphical interface for it.

So a lot of the time, maybe the graphical interface

will be buggy or crash

and the terminal program will still work.

Also, a lot of the penetration testing tools

do not even have a graphical interface.

A lot of them can only be used

throughout the terminal.

Not only that but in many scenarios,

you might only have an SSH or a command prompt access

to a machine.

So you need to know how to use this command prompt

in order to achieve your goals.

So throughout the course,

we're gonna be using the terminal a lot

and that's why I want to spend some time

just showing you the basics of it

and making sure that you're gonna be comfortable using it.

Now, the basic idea is you type a command

and the result will be displayed for you on screen.

So let's have a look on a very, very simple command,

which is pwd.

Now, this command prints the current working directory,

hence the name pwd.

So if I hit Enter,

you can see it's printing /root,

which means right now I am in the root directory.

So basically, I am in here.

This is the root, it's home.

So if I do ls,

which is a command to list all the directories and files

in the current working directory,

we should get all of these directories

that we see in here.

So if I hit Enter, as you can see,

I can see all these directories

in the current working directory.

Now, another very useful command is the cd command.

This command allow us to navigate into another directory.

So for example, let's say I want to navigate

into the Downloads.

All we have to do is type cd,

followed by the name of the directory

that I want to navigate to.

So I'm gonna type Downloads.

Now, if I hit Enter,

I should be inside the Downloads now,

so if I do pwd to see my current working directory,

you'll see that it's saying I'm in /root/Downloads.

So if I do ls here,

it should show me all the directories

and files inside Downloads.

So if I do Enter,

as you can see, I have a directory

and the file in here

and these are the exact same files

that you'll see if you double click the Downloads here.

Now, if you want to go back one directory,

so similar to pressing the back button in here,

all you have to do is cd,

again the command to change the working directory,

followed by the dot

and now if I do pwd,

you'll see I'm back in root

and if I do ls,

you'll see all the directories and files in root.

So that's all good.

And there's actually a huge number

of commands that you can use.

So I'm going to include a link

in the resources of this lecture

of all the Linux commands that you can use.

You don't need to know them by heart.

We're actually gonna be using a lot of them

throughout the course,

so you're going to naturally learn them

as you go through the course.

Now, if you are using a command

and you're not sure about how this command works,

you can just use the man command

to display the manual of this command.

For example, we've used the ls command here

to list the files and directories

in the current working directory

but if I do man, followed by ls,

this basically means I'm requesting the manual of ls.

So I'm asking how can I use the ls command?

So if I hit Enter,

you'll see I'll get a screen similar

to a text file and basically,

it's giving me a lot of information

on how to use the ls command.

So you can see that it's telling us

that this command will list the directory contents.

You can see the way it works by typing ls,

followed by the options, followed by a file

if you want to run it on a file.

You can see a longer description of the command.

And then you can see all the options

and the arguments that we can use with this command.

Now, in Linux, most of the time,

the options will always follow the same syntax.

So you either use dash letter

or dash, dash a word

to specify the argument.

For example, in here, the -a and --all

will ignore entries starting with dot.

So if you keep going down in here,

you'll see all the options and arguments you can use

with the ls command

and we have another example here.

We have the -l,

which manes it's going to use a long listing format,

which will display more information

about the files in the current working directory.

So let's have a look on that.

I'm gonna press Q to exit this.

And then we're gonna do ls as usual

and since we read the manual,

we know we can do -l to see more information

about the files.

And if I hit Enter now,

you can see I'm still getting the same directories

but it's also showing me the permissions,

the users, the date created and so on.

So you can use the man command

on any command you want,

not only on the ls.

So you can use it on the pwd,

you can use it on the cd

or any other command

and it'll show you a full description

or the manual page of how to use this command.

Now, I'm going to clear the screen by typing clear.

And the next thing that I wanna show you

is the --help.

So this is something that you can use again

in almost all commands and all programs in Linux.

So you can just type the program name

or the command name, followed by --help.

As you might think, this will show you a help message,

telling you what this command is

or what this program is,

the arguments that it takes,

how to use these arguments

and examples at the bottom.

Now, another useful thing

with the terminal, so I'm gonna clear this again,

is the arrows.

You can press up to go up to see all the commands

that we executed before

and again, you can go down to see to navigate

between the commands that you executed previously.

You can also use the tab for auto complete.

So again, let's do ls

and you can see all the files.

And let's say we want to go into Documents.

So we can do cd followed by Documents.

You can type Documents

or if you're lazy like me,

you can just do Doc and press Tab

and as you can see, it's automatically completing the rest

of the word for me.

So this is something that comes very, very handy

when you're using the terminal for a long time.

Now, what I also wanna show you

is how to install programs in Kali from the terminal.

So first, I'm gonna clear this.

And the first thing that you wanna do

is update the sources where Kali

can search and download programs from.

So we're gonna do apt-get update.

Now, apt-get is the name of the application

that allow us to download and install programs

and we're saying update

because I'm saying that I want you to update the list

of all the programs that I can install.

So I'm gonna hit Enter.

And you wanna make sure that you have internet connection

when running this.

And as you can see, it's telling me that it's done

and now we can go ahead and start installing applications.

So the first program that I wanna install

is actually a terminal program,

so similar to this one,

but it allow us to have multiple terminal windows open

in the same window.

So in order to install a program

through the command line,

we're gonna do apt-get, which is again,

the name of the program

that allow us to install programs on the system.

We're gonna say that I want to install

and the program that I want to install

is called terminator.

So very, very simple.

First of all, we're typing the name of the command,

which is apt-get.

We're saying that I want to install

and the program name

that I wanna install is called terminator.

So I'm gonna hit Enter.

And this is going to download and install terminator for me.

So you can use the same command to install any program

that you want.

You just need to replace terminator

with the name of the program

that you want to install.

Now, I've already downloaded

and installed this before,

so it didn't ask me to confirm.

But if you're running this for the first time,

it might ask you to confirm whether or not you actually want

to install this program.

So all you'd have to do is press Y

from the keyboard and hit Enter.

Now, as you can see, it's done.

So if I go to my all applications in here,

and just type terminator,

you can see that I have it here.

So I'm actually gonna drag it

and put it in my dock so I can access it easily

in the future.

So now I can just click it in here

and that'll open terminator for me.

Now, this is another application

that allow me to run commands.

So it's exactly the same as this.

So again, I can do ls and pwd.

The only difference is with this one,

I can actually right click

and click on Split Horizontally, for example,

and this will split the same screen

into two screens where I can run commands at the same time.

So I can have some commands in here

and I can run commands in here.

And then I can even split this more if I want,

again vertically or horizontally

and as you can see,

I can have as many terminal windows as I want

and this will be very helpful in the future

when we'll be running a number of programs

and a number of commands at the same time.

Now, before I let you go,

I just want to show you two websites

that I'm gonna include in the resources

of this lecture.

First of all, we have a website here

that includes the most common Linux commands,

if not all.

So you can go through them and familiarize yourself

with them, but keep in mind,

you don't need to know them all by heart.

Like I said, as you go through my course

and as you continue on with your journey,

you will learn the commands that you need as you go.

Another really useful resource

that I'm gonna include is explainshell.com.

This website is designed to explain Linux commands to you.

So all you have to do is type the commands in here.

So for example, if you just type ls,

and hit Explain,

it'll explain that ls will list directory content.

You could make it more complex

and do ls -la

and if we hit Enter now,

it'll break all the arguments

and explain every single argument.

So again, ls lists contents.

If we highlight the l,

as you can see, it's telling us

that it's going to use a long listing format

as we've seen earlier

and the a at the end is the same as -a,

which is all, which means that we do not want

to ignore entries starting with a dot,

so we do not want to ignore hidden files.

So you can do any command in here.

You can do apt-get install for example

and I'll actually explain it to you.

So it'll explain apt is a package manager

and install can be used to install packages and so on.

So if you ever see a Linux command

that you don't understand,

you can always just come in here,

put the command and it'll break it down to you

and explain it really nicely.