Original subtitles

‫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.