Introduction to Linux | Linux Full Course 2026 | Linux Tutorial for Beginners | Simplilearn

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[Music] Hey everyone, welcome to our Linux full course by simply learn. If you want to build a career in cyber security, you must know Linux. It's not just another operating system. It's the backbone of almost every hacking tool and security environment. So whether you're defending networks or testing vulnerabilities, Linux skills are what truly sets professional apart. The demand for Linux experts is growing fast as companies worldwide rely on Linux based systems to protect their data. Mastering it opens doors to highpaying roles across cyber security, DevOps and cloud computing. In this Linux school course, we will take you from beginner to job ready. You will learn how Linux file system work, why experts prefer it over Windows, and master the 50 essential Linux commands every security pro uses daily. We'll also dive into Kali Linux, the go-to platform for ethical hacking, and wrap up with key interview questions and answers to help you prepare for real world roles. And by the end, you will have the confidence and skills to thrive in the cyber security world. So guys, let's get started and make Linux your competitive edge. And hey, if you want to watch more videos like this, hit that subscribe button and check to our channel for more such tips and tutorials. Now, before we commence, here's a quick information. If you're interested in a futurep proof career in cyber security, simply learn professional certificate program in cyber security is the perfect starting point for you. This is a 20week program in collaboration with pin university and IBM equipping you with hands-on expertise in tools like metasplot it burp suit and map and exploring genai in cyber security with real world projects guided by industry experts. The demand for skill professionals is skyrocketing and this program provides you the certifications, skills and confidence you need to know to excel in the cyber security field. So guys, hurry up and enroll now and you can find the course link below. If you've ever opened a computer's file manager, you have probably seen something familiar on Windows. It's that trusty C drive with neat folders like program files and documents. On Mac you get applications folder your desktop and few others easy right but then you step into Linux and suddenly you're staring at bin etc proc lib and you're thinking what alien planet have I just landed on now the truth is Linux organizes its file in a completely different way drive no fancy icon everything starts from a single slash and every folder hanging from it has a very specific job. And here's the thing, it's not as scary as it looks. In fact, once you understand it, it's beautifully logical. So, in this video, I'm going to walk you through the Linux file system structure step by step in plain simple English. No tech jargon overloaded. And by the end, you'll know exactly what each folder does, where to find your stuff, and how it's different from Windows and Mac. So, in this video, we'll be covering what the Linux file system is and how it's different from Windows and Mac. Starting with the root directory and exploring key folders like home, bin, dev, lip, temp, and many others. We'll also cover simple Linux commands to navigate and explore the structure and a few quiz questions to make sure you're following along. Now, before we get started, here's a quick quiz question for you. When you first boot up your computer, which part of the Linux file system do you think is responsible for starting the system? Home directory, boot directory, etc. directory. You can drop your guesses in the comment section below. Also, if you haven't subscribed to Simple YouTube channel yet, do hit the notification bell and subscribe for more such content by simply learn. So, let's get started now. Now before we get started, let's first understand what exactly the Linux file system is. You can think of it as the organization system for your computer. Now every file, program, and setting on your system is stored somewhere. And the Linux system is responsible for organizing all of that into neat directories and files. It's just like the blueprint for your computer's data storage, telling you where to find things and how they are connected. Just like a library has shelf, labels and categories to keep all the books organized in the same way the Linux file system works but with files and directories instead of books. So why do we need this structure? Well, in Linux the file system is a hierarchal structure which means everything is organized in layers starting from the root at the top just like a tree and the branches off into different directories each serving a specific purpose. It help manage data efficiently, ensuring security and allows the system to run smoothly and quickly. So why are we diving into the Linux file system today? So whether you're new to Linux or a seasoned user, understanding where files are stored and how everything is organized is very important for troubleshooting and system efficiency. Knowing the purpose of each directory will help you to navigate and manage files easily. This video will give you a solid foundation so you can confidently handle task and feel in control of your Linux system. Let's have a quick comparison between Windows and Linux. So when you're using Windows, everything feels familiar. You've got your C drive, maybe a D or E drive, and all your files and programs are neatly stored there. file paths uses backslashes like users Alex document and Windows doesn't care about capital letters. So you can see here in the screen you can see most of the apps are installed and it's end up with C back slash program files right and also talking about the capital letters now files txt and files are treated the same. Most apps you install end up with C program files. So it's pretty straightforward. But here in case of Linux, it's pretty different. The rules are a little different. There are no drive letters. Everything starts with a single root directory and from there all your folders and files branch out. File paths uses forward slashes like home Chris downloads and it's also case sensitive. So filet txt and file.txt takes here completely different files here. Now another big difference is in Linux everything your hard drive your USB sticks even your keyboard appears somewhere under this slash. You can think of it like this. Now Linux is a giant tree and this slash is the trunk and every folder is a branch out here. The bin etc home opt and everything. Now once you see the pattern it actually becomes easier for you to navigate than in Windows. All right. Now, let's talk about the Linux file hierarchy structure or simply how Linux arranges the folders and files. Well, in Linux, there's something called the file system hierarchy standard or FHS for short. You can think of it as a rule book that tells the system where different types of files should go. Now, this standard is managed by the Linux Foundation. And here's the interesting part. No matter where a file is stored on your computer's hard drive or external drive or even a virtual device in Linux, all of it appears under one main folder which is the root directory. Now this root directory is just under a single forward slash. Some folders you'll see only if certain features are installed like the X window system for graphic but most of these folders are present in all Unix space system and they generally work in a very similar way. What we'll be focusing on here is how Linux uses them specifically. So let's dive into the structure and break it down step by step. Let's begin at the top the very first directory in Linux which is the root directory. Now what is a root directory in Linux? Well the root directory is like the main entry point in Linux. It's represented by a single forward slash and everything else in the system connects to it. You can think of the root directory like the trunk of a tree and all the other directories like branches grow out from it. This is the highest point in the Linux file system and there is nothing above it. It's the starting point for everything. Now how does the root directory even work? Well, every file folder device or even a network shared in the system is connected with slash. Let's say for example your documents, music files or even your external devices like USB drives. Everything will appear under the folder slash. But only the root user that is the administrator can make changes directly to the slash directory. Normal users won't have the permission to modify things out there without special access. Here's an important clarification to make the root versus this slash. The slashroot versus the normal slash. So this is the main root directory and the root is a special directory is the personal home directory to the root user and it's very similar to how the home username in a home directory is used for other people. You can think of flute as the roots user personal workspace within the system. Now in Windows we use different letters like C drive, D drive to represent different parts of a system like your hard drive, external storage etc. But in the case of Linux, there's no such thing as drive letters. Instead, everything connects to a root directory, even if it's an external devices like a USB drive. This structure makes Linux more unified and flexible as all the files, no matter where they are stored, are part of one system, which is starting from slash. All right, we are at the trunk of the tree. Let's grab the essential tools we'll need, and they are all in the bin folder. Now the second directory we're talking about is the bin which is essential user command. Now the bin directory Linux it stands for binary and it contains essential commands that every user can use. So whether they are an administrator or a normal user. These commands are the core tools which are required for running the system and doing everyday task for the terminal which is the command line. But why is bin even important? Well, the commands in bin are vital for working with files and managing your system. Let's say for here ls which stands for list the files in a directory. The cp stands for copies file or directories. MV means move or renaming files. RM is removing files or directories. Pink means checking network connectivity. GP searches for specific pattern in files and cat will display the contents of a file. You can see these commands are so fundamental that they are available even in single user mode which is a minimal state where the system can run in often used for maintenance or troubleshooting. So what happens if you don't have bin? If you don't have bin you wouldn't be able to perform basic file operations like copying, deleting or listing the files from the terminal. Now these actions would be impossible making the system unusable for normal task. If you're familiar with Windows, bin in Linux is similar same as in Windows like how we write this in C drive, Windows system 32 folder. System 32 in Windows holds essential tools like command.exe and other system utilities which are similar to how bin stores essential Linux command. So bin is critical directory in Linux because it's hold the basic commands that are necessary to interact with the system and manage file. Without these commands, the system wouldn't function properly. But before you can even use bin, Linux needs to actually start up. And that's where boot comes in. Let's make sure you're following along. So, I have another quiz question for you. Now, which of these folders in Linux holds the command that help you manage files like copying and moving them? Your options are home, bin, boot. You can think your answer and you can drop it in the comment section below. Now we'll be talking about the boot directory which is often called the boot loader and kernel files. Now this is where Linux keep everything it needs to start from the system. It contains the Linux kernel the core of the operating system. It holds the grub which is the bootloadader files the menu you might see when starting the computer. Now it also includes initial RAM disk file which is the initrid or init to help the kernel load drivers before the main system even starts. Now without boot your PC won't even start Linux. Talking about Windows, window has boot files like boot mgr and the boot configuration. Okay, the engine is running now. Linux needs to talk to hardware as well, keyboards, disk and printers. Now this happens when they are stored in the dev directory. Now dev is for the device files in Linux. So in Linux hardware is treated just like a file. So in hard drives you have folders like dev SD1 dev NVM then you have USB drive, microphone, speakers, keyboards all have entries over here. Now talking about the two main components. So there are basically two main type of uh device files here. First we've got the block devices which store and transfer data in blocks for example hard drives. Then second we have the character devices which can send data one character at a time. For example, serial ports and keyboards. In Windows devices appear as E, F, etc. And in Linux, they appear as special files in dev. Now, how does Linux knows how to behave? Now, that's decided in the ATC directory. This stands for system configuration files. The configuration files, this folder contains all the systemwide settings in plain text. You have your network settings here, the DNS servers. Then you have the user accounts as well, startup services like etc and ITD etc. You can also open these files with any text editor because Linux stores configurations as readable text unlike Windows registry which is stored in special database. Now we have seen system settings. Now where do you keep your personal files? That's where we have our home directory which is for personal user directories. Now every user in Linux gets a personal folder under this home. So if your username is John, your folder would be home John and you can store documents, pictures, downloads and even your personal configurations over here. You cannot just modify other users folder without any permission. It's just like the Windows C drive where users join in Windows like how we use it. Now we have seen how this home directory works. Now to run applications, Linux needs shared code and this is where the lib directory comes in which is for shared libraries. So lib basically contains dos shared object files which are similar to DL files in Windows. Now these are used by programs in bin and spin to work properly. Let's say for example if bin ls needs to print colored output it might use a library in this lib directory to handle colors. Next we look at the Linux puts removable devices USB drives CDs and that's where media directory comes in. This is also called the automounted devices. So when you plug in a USB or you insert a CD Linux automatically it creates a folder inside media and it mounts it there. For example, we have media John my USB. Now, Windows will just give you the device a new drive letter. Whereas in case of Linux, it will treat it as a part of the single directory tree. Let's move on to next directory. Now, sometimes you don't want Linux to automount devices, right? And that's where the mount comes into play. This is also called the temporary mount point directory which is used by system admins to manually mount devices or network drives. Also it's great for temporary use and it also doesn't even affect the media directory from here. Talking about the next directory on our list which is the opt optional software. We all know that some software doesn't come with Linux by default. We keep it that in this optional software directory. Third party software and its files are stored here. Let's say for example installing Google Chrome manually might put it in this opt Google Chrome uh directory. So this was for this directory out here. Next one we've got the SB bin which stands for system administration command. Now for system maintenance admins use special commands. These live in this folder. It contains commands like IP tables, firewall, fisk, disk parting and reboot. So if you want to access the directory, you want to first initially start up and access the root. Next one we've got on the list is srv the service data root directory. So what it does is it basically stores files for services like websites, SRV, www or FTP servers, SRV, FTP. Now you must have heard about this uh directory which is the temporary files TMP. This is used by application to store short-term data and also it clears automatically after a reboot. Then we've got this uh user directory, user programs and data. So the first one we have is the user local. These programs are installed manually from the source. Second user program data directory. We've got a user bin. The user commands which are not in the bin folder. Then we've got the user sbin where the admin commands not in the sbin. And then we have the user li which are related to libraries. The next up we've got this process information directory. So this is a virtual file system showing live uh system data. So this particularly will show your CPU details, your memory starts and information about a specific running process. So now that we have covered all the important file directories, I'll show you a quick Linux command cheat sheet. So here first up we've got this ls which stands for list directory content. Second we've got this cd directory which is the change directory. We have pwd which stands for print working directory. CP source desk it stands for copy files or directories. Then we've got MV source desk which is move rename files. RM is for remove files or directories. Stop is for displaying system processes. PS is for showing process status. Chod permission file is for changing file permissions. ch OWN user group file is for changing file ownership. Grep pattern file is for searching text patterns. CAT file is for displaying file content. Ping host is to test network connection. SSH is for securing shell connection. And at last you've got WG URL to download the files. >> Imagine this, you are a protector of a digital world. Keeping intruders out and ensuring sensitive data stays safe. That is what the core of cyber security and at the heart lies Kal Linux the ultimate operating system trusted by ethical hackers and security experts. In this beginnerfriendly tutorial we are going to understand what Kal Linux is and why it is important. We are going to discover the most essential tool it offers. We are going to dive into the hands-on activities to practice the real world scenario. So let us start with understanding what is Kal Linux. My dear friends, Kali Linux is a powerful open-source Linux distribution is specifically designed for cyber security professionals like ethical hackers, penetration testers. So these guys can use this tool. Actually this tool is built on DBN. So DBM is a operating system and it comes with pre-installed over 600 advanced security tools to perform various tasks like penetration testing, vulnerability assessment, digital forensics and wireless network analysis. Kali Linux was developed by offensive security and it is widely used in cyber security training and certifications like OCP certification program. If I talk about Kali Linux, Kali Linux is a versatile offering various options for installation on virtual machines, USB drives or even as live operating system. Additionally, it supports Windows subsystem for Linux for seamless integration into Windows environments with clean interface and customizable setup. Kali is just not for professionals but it is also an excellent platform to learn cyber security. Now if I talk about advantages of using Kal Linux there are several one of them like first of all it has over 600 tools okay so which are pre-installed tools and which is specifically tailored for security professionals second of all it has wide support now in terms of wide supports it works on multiple platforms like virtual machines windows subsystem for Linux Raspberry Pi etc of all because of its documentation. Now it has extensive tutorials and forum for guidance. So you could see all over here this is official documentation of Kali Linux and you could see there's a very amazing documentation. It will help you with installation introduction. Then it has given option for USB Kalon ARM WSL cloud and many more. And finally you could customize this. It is fully customizable to suit specific tasks and workflows. Now let us move ahead and let us try to understand some of the known commands of Kali Linux. But before that let us learn how to install this on Windows. Now before installing Kali Linux I want you to make sure that you have Windows subsystem for Linux installed on your system. If not you can navigate to this website which is installing WSL. So you will get a Microsoft official website and in this you could see there are certain prerequisites. Suppose if you're using Windows 11 operating system so it should be higher than 10. Okay. Now just type on the PowerShell open PowerShell and just copy this and install this. So with this command you will be able to install Windows Subsystem for Linux. Now the next step would be installing Kali Linux. So you have to do nothing. Go on to the Microsoft store and just click install. Now since I've already installed Kali Linux and it is very easy process after that it will be very uh like comfortable for you to operate on Kali Linux. So you could see I have installed the minimal configuration all over here. Okay. So this is the Kali Linux terminal. So it has opened. Now we are going to learn certain important commands which will help you to understand and these are very basic Linux commands only. So you have to not worry about it too much. So guys let's try to understand our first command. Let us say we want to know the date. So the name of the date command is just date. And you could see you'll get the exact date of today and the given time. And since I'm connected from the Indian time zone, so it is showing IST 2025. That's a very basic command. Next command is cal command. So cal command basically displays the current month's formatted calendar in our terminal screen. If you require more advanced version of cal, you can install the ncal package on the Linux machine which displays calendar vertically and provides additional options. So for now we are fine with cal. Just type cal. Okay. So you could see I have not installed cal. So let us try to install. So type sudo apt install ncal. Now you can see all over here it is fetching all the packages and we have perfectly installed it. Now let us type cal. Okay I think so is still processing. Now you could see all over here we are getting calendar in the vertical format and you could see the month date and all over here. Okay. So that is one of the most uh amazing uh you know package encal. Okay. Next is a very basic uh Linux command that is cd. So cd is also called change of directory. Okay. So if you want to switch this command you know if you want to move to any directory so you could just type cd and the given directory name. Okay but we are now fine all over here. Now next thing would be cp. Now cp is also same command as one of the most important Linux command which basically helps you to copy files or group of files or directory to create the exact image of a file on a desk with a different name. So suppose uh let us say we are going to desktop. So let us try to first find out how many files do we have ls. Okay. So you could see we have no files. So first we have to create a directory. So let us say mkdir and just type demo. Okay. Now type ls. So you could see we have this file demo. Now type cd and go to demo. So you could see all over here we are now in demo folder. So that was one of the thing. If you want to go back just type cd dot dot and you'll be reved back. Now before moving ahead so ls let's talk about this command. So it is one of the most powerful and useful commands in kal linux. Okay. So ls command basically list all the directories or contents of the files. So with the help of ls command we can easily list out every hidden file or directory with say with lsa attribute. Okay and it helps you to you know find the list of directories present on your system. So that was one of the command. Now let us try to understand the CAD command. So basically the CAD command is one of the Linux uh one of the most commonly used commands permitting us to create single or many files and concatenate files redirect view and contain of you know any output in a terminal file. Usually we use the CAD command to display the content of a file. So suppose we created any file say let us go to demo. So with the help of touch command let us create one file. Okay, let us go to demo first and let's type touch demo dot txt. Okay, and now type cat and demo.txt. And see since we have nothing written all over here. So if you have already written then uh you could get out certain output like what's written. So suppose let us do this activity by writing certain thing. So you could see this is a demo file. You could see all over here we are in the demo folder and you could see this text file demo.txt and uh since we have not written anything so that's why it's not showing any output. So we have got a bit of hang uh around what are the basic commands of Linux and same thing will be used in Kali Linux. Now let us download some of the amazing tools because Kal Linux has support for you know lot of tools and let us try to do some hands-on activity on them. Okay guys now let us try to download N map first. So what is N map? N MAPAP is basically for network scanning purposes. So that's a very amazing tool. So you could see this is official documentation of N mapap. So if you want to scan any network then this is a very amazing tool and this is available in Kali Linux. So you could see the documentation is written all over here. So you could go to the reference guide and uh like you could see all these things which they have given. Okay. Suppose no it has description option summary target specification host port scanning basics. Okay. So let us click on port scanning basics. So you know so it has given you know about all these ideas and similarly we are going to do the same thing in the kal Linux. So let us try to install n mapap first. So as I've already told you that n mapap is a very powerful network discovery tool. So for installation purpose type this command sudo apt install and map. Okay some mistake was there. sudo apt install and map white. So you could see okay again we have done some mistake. So you could see we have correctly installed N mapap and uh now we could check the version number of the same. So type n mapap go on version. So you could see we have n mapap version of 7.94 and we are using Linux GNU platform. Okay. So it's you can see it has also given us compiled with lelua 5.4.6. Okay. Okay. So these are the certain information that you will get. Now let us do a one hands-on activity with this tool. So let us first clear it all. Okay. Now let us try to scan a network for connected devices and identify the open ports. So let us say we are targeting okay certain devices to a local network. So suppose we type end map and then SP okay then the given name of your IP address. So suppose we type this local address 168.1.0/24 and let us see. So you can see it has started scanning. Okay. And you can see host is up with this latency. host is up 0 055 seconds latency. So you you're getting a scan report on this uh given IP address. So basically what it is doing is this command is sending ping request and receives a list of live host. Now the basic command is suppose uh map SP and the given name of your IP address. >> Okay. Now next if you are trying to scan a specific device for you know open ports so what you could do so we could use the same IP okay and type n map okay /p and we're going to give 1 to 1 and let us say our target IP we are trying to take it as 192.1 168 8.1.0/24 and you could see it is trying to uh you know it is going to scan a specific device for open ports. So let us see whether this has it or not. Now you could you could see all over here we have got the report. So after you know targeting you know what devices are connected. So you could see the scan report. Okay. So host is up port you know HTTCP filtered the service is HTTP then this is another port then the service is HTTPS okay similarly you could see a scan report for all the devices you know you know a specific devices which are connected to this open port so that's one of the amazing uh thing and insight you could get now for you know service version detection you could identify services running on open ports also so what what command command you have to type guys just type n mapap and in this type sv and say our target IP is same 192.1 168.1.0 24. So guys as you can see all over here the service scan is done. So you could see the scan report is given and it is saying service detection performed. So you can see service info, operating system, CP. So it has given all these amazing thing. So guys with this tool what you could do one activity is find your router's IP address and then find the open ports and research the services associated with this. Now you will find a bit difficulty or even you'll be thinking how to find a router's IP address. So you could use this command guys. So you could use a Kalia Linux terminal and you could just type all over here IP route grab default. So you could see we are getting certain thing default you know IP 17228.8.1. So it is going to look something like this. So this is going to be your router's IP address. Now use the N map command. Perform the basic scan. Put that IP. Okay. Then uh perform detailed scan to identify the service with the help of you know this command and map SV and given name of your IP address and full report scan. How you could do it guys? So for a full report scan you could do N mapap P then the given router ID all over here. So this tool is very amazing and very insightful and you could research a lot of thing and get to know. Okay. So this is one of the amazing tool which is present in Kali Linux. Now let us explore some of the other tool. Now let us try to install Metas-ploit. So guys, first let us understand what is metas-ploit. So metas-ploit is a framework for developing and testing exploits. So what it does is it allows penetration testers to simulate real world attacks and identify vulnerabilities in the system. Basically metas-loit is usually pre-installed alcal in Linux but if not you could install with certain thing like this. type this command sudo app install metasloit and type y. Okay, so it is going to install metasloit framework. Since I have already installed it, so I I need not to do it again. And if you want to verify the installation process, type this command ms f console and type version. So you could see you will get certain thing like this. The version number is 6.4.34 dev. Now let us do a hands-on activity. Now let us exploit a vulnerable system using metas-loit. So first type msf console. So it is starting the metas-ploit framework console all over here. So you could see we have uh come up into this documentation. Okay. Now you could go on to the official documentation of metas-ploit. Okay, just copy this or go over here. So this is the official documentation of metas-ploit. You could read about it. You could read about pen testing, how to set up module options, upgrading shells to meter and lot of other things are there. So based on thing which you want to learn, you could just you know read this documentation. It's a very amazing documentation. So I will show you a very small or simple hands-on activity. So let us uh try to you know exploit a vulnerable system. Okay. So we have come into our console and let us look for SMB related vulnerabilities. Now you'll be wondering what is an SMB protocol or what basically is an SMB vulnerability. So as uh I can tell you that SMB is a vulnerability or a security flaw in server message block protocol or an SMB uh protocol that allows attacker to gain unauthorized access to a given network. So uh let us do this attack first. So type this command search SMB. So you could see all over here that we have got a lot of files as an output. Now what we are going to do we are going to select an eternal glue exploit. So you can type something like this. Use exploit slash Windows SL SMB/ MS 17 0 1 0 and eternal blue. Now what after this? So it's saying no payload configured defaulting to Windows XP meter printer reverse TCP. Okay. So this is MSF6 exploit. So let us say you know you could just after do certain thing like this set RH host first and give your target IP all over here and you could uh you know execute the exploit after this. So say we have the same target IP say 192 168 say 1.1 and after this just type exploit. So you could see we have started the exploit all over here. So it says that the target is not vulnerable at all. Okay. So similarly you could perform exploit for the given target IP. I deliberately chose this. Okay. So guys you could use this tool to deliberately target a system and simulate exploit. Now I'm going to show you one more amazing tool. Its name is Nikto. Okay. So Nikto is basically a web server vulnerability scanner that identify potential issues like outdated software misconfigurations and exposed files. So how you could install Neto? So type this command sudoapp install necto and type y. So you can see we have uh started setting up our nikto then type nicto version and you could see all over here that okay so this is not the command for version let's try this okay so you can see all over here we have the version of necto as 2.5.0 to okay so this is the latest version and now let us try to do a hands-on activity uh if you want to learn about Nikto just go to the official website so you could see it is Nikto 2.5 and uh you could read about Nikto so you could go and know read the docs like overview description you know and all those things so let's do one small activity so we are going to scan a web server for vulnerabilities. So let us say we target this website. Okay. So guys as you can see all over here we uh will take this as our given uh website. So just copy the link of this uh website and uh go on to your terminal and type nikto. Okay. Then edge then uh you could just give the name of you know given target website and since it is HTTP secured but I want it to be HTTP version of this. Now you could see uh so it's saying server no banner retrieve. So the anti-clicking extreme options header is not present. So target IP is this target host name is this target port start time and you can see this uh you know uh it says that this is basically you know secured website no vulnerabilities like uh things are being found. So you can see also the X content type option header is not set. Okay. So you could do a lot of other things like uh with this. Now what you could do next is uh suppose we use the same IP address. Okay. And let's type okay and next what I'm going to do all over here is this that uh for detailed SSL checks and header what I'm going to do I'm going to type SSL and capital C and so you can see all over here it is going to give you a detailed uh you know output uh with the help of this command. Now you could see since it is a very secured website so it is not showing that thing but suppose if you're building any W website or you are just into you know the development phase of building a web application then you could use this tool to test the given vulnerabilities. So what you could do there is one exercise like you could set up a web application suppose say you are making a juice shop and you could use this tool to identify the given vulnerabilities. So guys, we have showed you some of the tools and what's uh the power of Kallay Linux is and how these tools can be easily worked upon Kal Linux to do the exploit to do the testing and perform a detailed analysis of the given server devices. Okay. And services also basically the tools which I have showed you represent the core of what makes Kali Linux so powerful for cyber security professionals. So by using the tools like end mapap, metas-ploit, nikto, you have gained a bit of hands-on experience with network scanning, packet analysis, exploitation, how to do brute force attacks and web vulnerability assessments. If you do a regular practice with these tools, it will help you to improve your skill and it is also going to help you to understand the importance of ethical hacking and securing system that is Linux versus Windows. So Linux, an open-source and complimentary operating system, debuted in 1991 courtesy of Linus Strows while he was a student at the University of Helsenai. Drawing its foundation from the unique system, Linux is acclaimed for its robust stability, enhanced security, and versatile adaptability. It's extensively utilized across various platforms, including servers, supercomputers, mobile devices, embedded systems, and desktop computers. On the other side, Microsoft is the architect behind the proprietary operating system Windows. Launched initially as Windows 1.0 in 1985, it served as a graphical overlay for the MSTO system. Over the years, Windows has evolved through numerous substantial updates. This operating system is prevalent across a broad spectrum of devices encompassing personal computers, tablets, and other similar technologies. While Linux has established dominance in server and supercomputer applications, Windows enjoy widespread popularity in the personal computing realm. Windows is often loaded for its user-friendly interface whereas Linux is celebrated for its formidable stability and security features. In the past few years, Linux has seen a surge in its adoption as a desktop operating system. This rise in popularity can be attributed primarily to the emergence of accessible and userfriendly versions like Ubuntu and Mint. Despite this, Windows continues to maintain its stronghold as the global preferred desktop operating system. Nevertheless, Linux is steadily carving out a significant niche for itself in the market. Now moving to the difference between Linux versus Windows. So starting with first that is Windows uses different data drives like CDE to store files and folders and whereas Linux uses a tree like a hierarchical file system. Linux files are ordered in a tree structure starting with the root directory whereas in Windows files are stored in folders on different data drives like C, D or E. Now moving to the next difference that is hard drives, CDROMs, printers are considered as devices and whereas in Linux peripherals like hard drives, CDROMs, printers are also considered files in Linux or Unix systems. Now moving to the next difference that is there are four types of user account types in Windows that is administrator, standard, child and guest. Whereas in Linux there are three types of user account types regular, root and service account. Moving to the next difference. So Windows administrator user has all administrative privileges of computers. And in Linux root user is the super user and has all administrative privileges. And now moving to the next one. So in Windows you cannot have two files with the same name in the same folder. Whereas in Linux you can have that is the naming convention is case sensitive. The sample and the case uppercase sample are two different files in Linux or Unix operating system. And moving to the next difference in Windows my documents is default home directory. Whereas in Linux for every user directory is created which is called his home directory. And talking about more so Linux is an open-source operating system. So user can change source code as per requirement. Whereas Windows OS is a commercial operating system. So user doesn't have access to source code and Linux is very well secure as it is easy to detect bugs and fix whereas Windows has a huge user base. So it becomes a target of hackers to attack Windows system. And if we compare Windows file system versus Linux file system, Linux runs faster even with older hardware whereas Windows are slower compared to Linux. And in Linux, as you can see, you can have two files with the same name. And in Linux, you would find the system and program files in different directories. Whereas in Windows, system and program files are usually saved in C drive. We are diving into 50 Linux commands that are absolute mustnows for anyone using this powerful operating system. So let's get started. So now let's get started. And the first thing we have to do is open the terminal. So we'll just press Ctrl Alt P and here's a terminal and we'll get started with the commands now. So the first command we'll see here is ls. So what does ls do? It lists all the files and directories in the current directory. So as you can see we are on the home screen only. So it has listed all them that is desktop, documents, downloads, music, pictures, public, snap, templates and videos as you could see. Uh so this is the home screen and these are the directories that are listed in the home and that this ls command has provided all the directories here and I'm running the Ubuntu and the virtual box for your information. So if you have the Ubuntu installed on your system so it's well and good and I was using Windows so I use the virtual box to install the Ubuntu and here we are running all the commands and if you use ls minus so it will give all the hidden directories also hidden stuff so these are the hidden stuff that was there so it has listed them also so now moving on to the next command that would be pwd And what does the pwd command do? It prints the current working directory where we are working. So pwd. So we are at home a visaruja. So this is our current working directory. And now we'll see the next command that is cd. And what does it does is change the directory. If you want to move to any directory, you can just write cd and the name of the directory. And we'll see which one will go to documents. We'll just write documents. and press enter. So now we are in the documents directory and with the command cd dot dot we'll jump back to the previous directory that is cd space dot oh sorry now you have been redacted to the previous directory that is home only and if you want to just get back to home you can just write cd space and click on you'll get back to the home as we are already on the home So we have not changed any directory and the next command would be mkdir that is to create a new directory. So for that we'll just write mkdir and the name of the new directory but you want to create. So I will create the new directory with the name abisar. So we have created the new directory. You can check here that aisar that has been created and if you want to remove that directory you just have to use the command rmdir space abisar and press enter. And that directive would be removed from there. That has been removed. And now we'll see the command to create a file. And this is the easiest way to create any file. So we'll just use the touch command that is to create a file. And after touch, you just have to write the name of the file. So I'll write a dot txt. So you'll see. So the txt file has been created here. So here we have cleared the terminal. And now we'll see another command to create a file that is cat. So just write cat greater than symbol and the name of the file that would be a bisar 2 dot txt. Okay. And press enter. And now you can write the content you want to insert in this file. So I'll write my name is Aishar and today I'm creating a video on Linux. Okay. And after writing this you just have to press control and D. So this will be inserted into your file. So after pressing the control + D this content has been inserted. So we can just check it. You can see here that the content is already been inserted in the file. Okay. So moving back now we'll see the next command that is echo. And echo is mainly used to get something to display in the terminal only. Or you just want to talk to yourself, you can use the echo command. So here I will write echo in inverted comma. So I will write simply learn and press enter. You could see that it has written simply learn. So it get backs the text or anything you want to display on the terminal only. And now we will see another command that is cp and that is used to copy files or directories. So here we'll use the command cp and here we'll copy a file that is uh avisar2.txt into documents. So for that we'll write cp after that the name of the file that is abisar 2 dot txt and then the folder name that was documents and then enter. Now we'll check in the documents we have the visard 2.txt file and that has been copied into that and the next command is mv. So if you want to move any file into any directory you just write mv and we have the file that is abhr txt. This file we will also move into documents. So we'll just write the name of the file that is pertur txt and txt and the name of the directory in which you want to move it. So that is documents dash and then enter. And now we'll check it. So you can see that it has been moved. So it has been moved from home to documents. And now uh we'll see another command that is rm that is to remove any file or directories. So from the documents only we'll remove the file aisar to do. TXT. Okay. So here we'll write rm aisar 2.xt. txt and from where you want to remove it that is documents. Okay. Uh can we it's a directory. Okay. So we'll just write this command. We are in the home. So first we'll move to documents sorry CD documents and here we will remove the file that is rmisard2.txt txt and now if we see that has been removed from here and now we'll see another command that is nano and that is also used to create a file or if you have the exact file what file name you will enter here if it's there it will open that or else it will create a new file so we'll write obvious 3txt enter and here you can directly like edit the file you could just write the file. So you could edit it here and write anything that is we are learning Linux and to save it we'll just press Ctrl X Y and then enter. So it has been saved. We are learning Linux. So this is also the mode to create a file and you would just go with the editor directly and you could just enter in the file and then to save it you just have to press Ctrl X Y and enter. And now uh the next command that is shred command. If you want to hide something or you want don't want to show any content in a file to anyone. So you will just write or use the shred command that is shred and after that file name that is [Music] that is file name 3 dot txt and press enter and we'll use cat to open that that is visar 3 dot txt and press enter you can see that it won't show any content to anyone. So after that we'll see another command that is htop and what does it do is uh like it's not found here and it's not installed. So if you want to install it just write this command that is sudo install htop and press enter. And now it's asking for password. And now moving on to the next command. We will create another window for that. Close these windows. Close this terminal. And in this terminal, we'll use the command less. And this command is used to view the contents interactively of the file. So we'll use less and see the contents of obiser.txt. txt press enter. So you could see that the contents are I am a viser and see that the content is I am a visa and now we will see another command and for that we'll create a new window and close the previous terminals and in the new terminal we'll use the gr command that is used to search for specific patterns words within the within the files. So, gp and then the special term that is abisar will search and then the file name that is abiser dot txt and press enter. So it will return the full sentence in which that pattern is found that is I am a bisar and you could see in the file that we have a bisar text and that is in the line I'm a bisa and it has returned us that and we go to the next command we'll use the find command and with find command you could search for various files or directories based on a given criteria so we will find the abhaser txt file here and like it has returned that we are in documents only and it has returned the ais txt file. So this was about the find command and moving on to the next command that is to change file access permissions and that command is chmote. So missing opin uh so we have to add the oprint also that is cho and we'll write 755 and the name of the file that is pubiser txt and press enter. So the permissions of the file have been changed here. And what does this indicate? So we have set the file permissions of aiser.txt txt file to read, write and execute for the owner and read and execute for others here. And if you want to change the ownership of the file, we will cut. And now moving to the next terminal. And here we will use the command gzip that is to compress the files. So gzip and then the name of the file that is abaser.txt txt and press enter. So it has been compressed. You could see that it has been compressed. And to uncompress or decompress the compressed files, we'll just write the command gun. And then the name of the file that is wert dot txt and it has been compressed. So the extension has been changed GZ. And now if you see that has been decompressed. So now we will use another command and now we will see another command that is date. So we'll just write date and you could see that the date has been printed and then we have command who am I and it will just showcase the current username that is absar and the