Pass CompTIA Linux+ XK0-004 Exam in First Attempt Easily

Course Introduction

1. Course Introduction 1

Alright, so here in Linux Plus, we're going to talk a lot about the obviously named operating system called Linux. Now you're going to see that there are many varieties of Linux, many distributions, or things we call "distros." So what we're going to do is instead of focusing on just one release or one company's version like RedHat, what we're going to do is really just focus on what's in common with all versions of Linux and let you understand how it functions, how it deals with just everyday management, file management, hardware, and everything else. So, regardless of which version you're using, you'll be able to use the commands, structures, and other features that we demonstrate with all of those distros. To start off with, we're going to talk about installation. Now, installation today is a piece of cake. We have CDs, DVDs, USB drives, networks, and downloadable images. There are all sorts of ways that we're going to be able to install the software. So it'll be kind of an introduction for us to talk about some of the things you might have to do depending on the versions of Linux that you decide to install, such as figuring out what hardware you have on your system so you can kind of go through what we call a preinstallation set of tasks to make sure that you don't have any incompatibilities. And then you'll progress from installation to booting it up and logging in to actually using Linux. Now when we talk about using Linux, we're going to talk about using their graphical user interface and their command line structure, or sometimes what we call command shell" or just a "shell." We want to make sure that we can do both. Now originally, Linux, as you're going to see, was a command-line-driven program or operating system, and adding on Windows was something that was really cool. Adding on, I know I sounded like I was using a Microsoft term, but that's what it was. It was a graphical user interface. It was putting up new windows. They called it Windows X windows. We're going to move into file and directory management. Now, a lot of assumptions are made that you are already familiar with the Microsoft Windows environment, so I'm going to spend time making sure you understand how file and directory management are similar and different in the Linux environment. We're going to talk about the directories, the organizations, the file manipulations, creating files, deleting files, talking about how volumes are organized, and the entire file structure hierarchy. We're even looking at removable storage and what it takes to be able to manage all sorts of different devices, whether USB or CDs and the rest of them. From that point, we're going to move on to system administration, where we're going to look at what is common to most operating systems, namely authentication, authorization, and sometimes even accounting or accountability. But we're going to start off by looking at users and groups, how you create them, issues about their default settings, their home folders, passwords, and those types of things. We're going to take a look at those users and groups and associate them with file and directory permissions. We're going to talk about being able to use different types of configurations as defaults for each of these devices or objects that we make because it is true that we can make it very easy or very difficult to create users. So we'll talk about that, and then we'll even look at how you can use the GUI to be able to do a lot of the same types of administration that we will also be doing through the command line. So, you've heard me say command line and GUI before. We're going to be doing both throughout this course. We're going to move on from there into application management talked about packages and what it means to take a package and install that or to work with a package of applications rather than just a single file that I compile and run. We're talking about package managers, and we're going to talk about the source code of the software, and it's going to give you, I think, a kind of insight as to what programmers really love about Linux as an operating system. Then we're going to move into the system configuration. We're going to talk about disc management, and a lot of the information we talk about is going to be common to every operating system because we will talk about the actual hard drive itself, which is the same whether it's in a Linux machine, a Macintosh, Windows, or whatever it is. We are going to talk about some of the file system options that you have supported and some of the device management. Again, also going back into the removable media, we're going to talk about process and module management, which really means we're going to talk about programs and programs that are running and timesharing with the CPU and how you can give some processes higher priority than others or how to kill those processes that won't die or that you're trying to get to stop running. We'll talk about the kernel module. We'll move from there into system maintenance. From there, of course, it means whatever system maintenance sounds like in any operating system, and that is, if the worst happens, can I get back online quickly? That means backing things up and being able to restore those backups Talk about scheduling tasks. You don't have to basically bore yourself every day with the same mundane or routine types of tasks. You can schedule those. We'll talk about logging, performance monitoring, and other types of things that all fall under system maintenance. And yes, if you've taken a Windows course, you've heard all those terms before. That is a very common part of any operating system, the maintenance, and that means that you have a baseline for what happens. that you take care of routine tasks and, of course, backup and restore.

2. Course Introduction 2

Now, Linux was designed to work well with networking. So we're going to get into networking, and we're going to talk about networking basics, the network services that you have, domain name services, and all of the things that make working on the network viable for us us. That includes understanding how the domain names help us with making the connections. And then when we do make connections to the network, we're going to then move into resource sharing, specifically talking about file sharing and printing. So we'll talk about the network file service, or NFS. We'll talk about printing and how to make that work. And also on the network are other devices besides Linux machines. So we'll get into interoperability, basically knowing that I can have my Linux machine talk to a Windows machine, to a router, or to something else that might not be using the same operating system, but because of the networking technologies and the protocols, we have interoperability. So we'll talk about that. We'll also look at using the network for remote access as well. Now that we have remote access and networking access from the outside, suddenly security becomes the next issue that makes sense that we talk about. We're going to talk about system security, network security, and you have to be careful because I love talking about security, so I might inadvertently go down a couple of different avenues and talk about issues you should be aware of, but it's just to make sure you're as secure as possible from there. Another method of remote connection, of course, is the Web environment, my hosting web server, or Web services. So you can connect and look at my Web page. I might be using a database to power your Web page. So we'll look at MySQL or the MySQL service as well. Other types of communications that we use with the network would be our FTP, the file transfer protocol, and email services. So we'll talk about both of those, how the FTP service works with Linux, and how the mail servers run. And then finally, we're going to wrap it all up with troubleshooting and maintenance, which, of course, happens in every operating system. We want to understand the process of what to look for in making reparations, whether it's booting it up or network troubleshooting, or whether or not we're going to deal with any of the other types of scripting basics that we can use to bring things back together. I mean, we're going to talk about troubleshooting so that hopefully you aren't going to have to just reinstall, lose all your content, and start all over again. We want to make sure we cover all of the issues. So that's our goal. Again, you didn't hear me talk about a specific distribution of Linux. We're going to talk about commands and options that are common to all the versions of Linux that you're going to use, so that from that point you can decide which version of Linux is appropriate for you. Maybe it's one you already have installed because of work or on some networking device. However, you will have the option to do so. We're going to make sure you understand how to use the operating system.

3. Instructor Introduction 3

Hello. My name is Ken Mayer, and I'll be your instructor here for this Linux Plus course. Now, in the past 37 years, I've been working on a variety of different platforms, operating systems, networks, servers, and everything else that you can think of. That's because in that time frame, stuff has changed. I started punching cards on the machine to make Fortran code. I remember when Unix systems first came into our universities, and I was like, "Wow, this is really annoying. I don't like it." And I thought I'd never see Unix again when I got through with this stuff. Then I went into this novel world in Microsoft Word, and all during this time, what happens? Linux comes out, we start hearing more and more about it, and suddenly it becomes a part of Novel. And I see it as the foundation of all the networking devices that I use for routing and switching, and it's just everywhere. And then, of course, as I got really big into security, I fell back in love with Linux. So anyway, we would say that we love and hate this operating system on and off again. My goal is to make sure that I can take all of my experience using it as a platform for network devices, using it as a hacker, using it in large institutions, and all of the different ways in which you can use and I have utilised Linux. I hope all of that experience will be able to help you understand how you can use it to give you the commands and the information that you need to be able to make it work well for you and, of course, make it secure.

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Unit 01 – Installation

1. Installation

Alright, so we're going to start off by talking about installation. Now I know a lot of you are going to say, "Really?" Installation? I mean, come on, was that throwing in a CD-ROM drive? Well, yeah, it is. But it's going to be a little bit more than that. We're going to talk about what Linux does. It's kind of an introduction; talk about its role in the world of networking. We'll talk about ways in which you can download Linux, create an installation disk, and then talk about the options you have for installing and doing the basic configuration of Linux. So even though it does sound pretty rudimentary, there are some things you should know, some options that you have, and some really kind of cool ways that you can get Linux up and running on your operating system, whether it's permanent or whether it's temporary. So let's go ahead and take a look at what it means to say "installation."

2. Topic A: Linux Introduction

Alright. So we're going to start off in this unit with our first topic, which is, just as I said before, an introduction to Linux. Now, let me just say something right ahead of time. There are so many people that are so crazy-easy about Linux that they have their own language, their own terms, and their own way of pronouncing things. And then there are people who pronounce things differently. But it's the same word. For instance, Linux I've heard of Linux. I've heard of Linux. Now, the reason I'm saying this now is that I want to get out of the way. If I pronounce something differently than you've heard, it doesn't mean I'm wrong. It just means it's not the one you heard. If you don't like it, I apologise ahead of time. But it's just the world we live in today when we deal with Linux. So I'm warning you ahead of time. I've heard it all along. Is it, for example, gentle or gentle for one of the distributions? All of these things are little minor pieces that I'm not going to dwell on throughout this course. So I thought that would be a great way of saying, Let's have our introduction to Linux. I'm going to call it Linux. If you like calling it Linux, go ahead. Just pretend in your mind. That's what I said. Okay, so we're going to start off right now and talk about it as an introduction.

3. Ubuntu with OpenOffice / Firefox

All right. So as an example, we can talk about different varieties of Linux. And there are first of all, it's Unixlike. Now, it's, I think, important that we say "Unix-like" because it's not Unix. Unix, of course, is its own operating system. But much of what we use with Linux looks like Unix. It was developed by Linus Torvalds in 1991 while he was a student in Helsinki. He left it as an open-source program, meaning that you could take it, you could change it, you could reverse-engineer it, and you could alter it, but you could not charge for it. It was something that was freely available to the open source world as an operating system. It did what operating systems needed to do. It handles your common operating system needs—your file management, user accounts, and the input and output with a variety of different types of hardware devices, including, of course, the rudimentary keyboard, video, printer, and those types of things. Since then, the world of Linux has provided us with a plethora of different distributions. You'll hear different types of names for the different options that you have. Of course, one of the big sellers is Red Hat. Now, suddenly somebody looks at me, and they say, "Wait a second, seller." Yes, Red Hat does sell this operating system, but we'll talk a little bit about that in the licensing. But remember, they're selling other things like service and education and other features that they've added on. There's a large amount of readily available software that you can use with this operating system. need a web browser. You can use Firefox. You need to have a Word document where you don't use words. You use Open Office and create your own documents that are like Word documents. Your own spreadsheets, your own presentations In fact, almost all Windows programs are already available in the Linux operating system as a replacement. and again, almost always for free. I like that. For free. It sounds really good. Maybe I should say it again and again. Now, having said that, I'm not saying it's better or worse. Please. I'm not getting into that game. As a hacker, I can tell you that I can give you the pluses and minuses on both sides of this in the world of security. As a person who deals with businesses, I can give you pluses and minuses for going in either direction in the support of your business. It is a tool that may or may not meet your business needs. It may be something you personally like to work with better than other options, whatever the case may be. But there is yet to be a perfect operating system. Now, once I make that perfect operating system, I'll release it all to you, and I'll become the next billionaire. but right now there isn't one. So again, just like I said before, we have this variety of ways of pronouncing the different terms and the different acronyms. There's also going to be a huge debate over which is better to use. I'm not here to take part in that debate, and I'm not here to favour one over the other. I want to make sure, if you choose to use Linux, that it works well for you. That is why we say the entire world uses Linux. There are a variety of different types of distributions. There are different versions of Linux that you can use. and it's important that you pick one that has the features that you like.

4. Linux Platforms

Now, as I said, when it comes to the Linux platform, Linux was designed to be able to run well on servers to give you an enterprise-class computing environment. Now, one of the big proponents of that is Red Hat. Red Hat has an enterprise solution. What it means to have an enterprise solution is that they have tuned their version of Linux, as well as all of the other middleware that you require, to provide you with a fully ready, server-wide solution at a very low cost. A lot of what you're paying for is not actually the Linux code or the Linux kernel itself, but for all the add-ons that they've given you and the support that they have if you call on the phone and have issues. We also see Linux-like or Unix-like operating systems running on different types of network devices. You might see them on your Juniper routers or your Cisco routers and switches. It's a very popular operating system. We see it in the use of Novell. In the current releases from Novell for your network operating systems, you're finding a lot of underlying Linux, Unix, or Unix-like solutions. Now, I'm also saying "Unix like" a lot because some of these versions use BSD, which is not Linux, it's not Unix, it's Unix like. It's kind of a sticky point that we want to make sure we're not saying it's Linux or it's Unix, but we're saying it's like them. Just like when we said Linux is Unix life, I know you're wondering why I'm jumping around all of these semantics; you'll see why I'm doing that in just a few more minutes as we talk about licensing, why I'm doing that. I'm just doing it now. won't keep doing it all the way through. Okay? Linux also comes with availability for your desktop and end-user computers, including your handheld phones or PDAs. For the longest time I had a PDA made by Sharp. It was called Azoris, and it had a Linux shell or Linux kernel loaded on it. And I would utilize a lot of the Linux platforms to be able to do things like war walking, looking for WiFi, capturing the packets, and doing all those really cool things that I could do very easily in the Linux environment. We also see it embedded, as I said, into no computer devices. Returning to routers and switches, a company called Viata is attempting to compete in the realm of small enterprise routing against Cisco, Juniper, and all of those companies by offering a device that is running a Linux or Linux-like environment and running their software and running these devices off of that platform. So we see Linux, let's say, everywhere. It's there very prevalently, but not with the average user, because the average user is still seeing Windows desktops when they log in. And not very many of them actually get into these end devices and see them on their phones, on their PDAs, on the routers and switches, on the firewalls, and all of these other solutions. So it's popular. It's everywhere. And, as I previously stated, it has a wide range of applications, from the home user to the small device to the enterprise class server.

5. Linux Platforms

Now, there are many different distributions that we often call distros. There are many popular ones. Here we go with the fun of trying to figure out how to pronounce this one: Ubuntu, or Ubuntu, which is currently one of the most popular end-user versions we have. The reason people like it is because it's easy to use. It supports multiple languages, which are the goals, or at least two of the biggest goals, for developers. Many developers don't want to fight against the operating system to be able to develop their code. In fact, some people would argue that one of the popular points of Windows is that it's very easy to create programs for it because it's going to be universally the same everywhere. In other words, the program they create on this system will run on this one and this one and this one. And they don't have to worry about dealing with different hardware platforms or anything else. They just do it with Windows. One of the reasons it is so popular is that Red Hat Enterprise Linux is designed for both servers and desktop computers. They also provide you a lot of middleware support and education. In fact, I'd say Red Hat does a lot to help push forward the use of Linux and the knowledge of people wanting to get certifications and understand what it does. Fedora would be Red Hat's enduser distribution, or Linux distribution. Sousa, which I believe is now owned by the Nobel Corporation, is their version of Linux once more. Now, having just said this, and all of these different distributions, or distros, as they like to call them, can be downloaded for you, with the exception, as I said, of Red Hat for the Red Hat Enterprise, you actually pay a price for the licencing of all of the things they give you. Most of the rest of them can be downloaded for free. And you must decide why you prefer Fedora over Sousa, or any other, or gentle. Or gentle, or any of the rest? Why would I choose that? When we try to hit that, as I talk about some of these other popular distributions.

6. Linux Platforms

Okay, debian is another one. It is, once again, a platform or a distribution community—created and managed by a consortium of open-source, shall we say, members who can contribute and continue to develop and improve the version. It's considered to be very customizable and a very powerful distribution. Slackware, one of your oldest distributions, is out there still active. It has active development that is being used now for power users. And here's where I can kind of wrap up all of this. Why do I want one over the other? by talking about two others that are very popular: backtrack and helix. Now, Backtrack and Helix are examples of distributions of Linux that have a very specific use. And what I mean by specific is simply that this backtrack is known as a hacker's toolkit. What happens, you see, with Backtrack is that when you install it, it instals with all—and I mean, like all—of the latest and greatest tools that a hacker would ever want to be able to do a penetration test against a network. I mean, it has all sorts of phases, from the scanning, the enumeration, the tracing, and the hacking into the buffer overflows. I mean, it's got it all. It's all ready to go. You don't have to install these tools. Helix was a great distribution to use for doing forensic investigations on other machines because, again, it has all of the tools, a lot of PS tools, and a lot of software to be able to basically do your own file carving, your own analyzing, your own copying or duplication of drives; everything's there. So one of the things that I use Backtracking and Helix for are my examples to say, "Why would you choose one distribution over another?" And the answer is, What are your goals? What are you trying to solve as a solution with your choice of Linux? Because some of these come with the tools already prepared, already installed, and ready to run, while others may have none of them but be the foundation from which you can build your own. And maybe that's what you want. If you're the power user, you're going to say, "You know, there's a lot of stuff on Backtrack I'll never use." I don't want it. I want to build my own from this foundation. And by the way, from what I've just told you, there are many other versions out there. I would almost venture to say, without bragging or exaggerating too much, that there are hundreds of different distributions that are available to you and lots of websites that you can go to and actually search for the different types of Linux that are out there. And all of them, as I said before, you can download and install.

7. Software Licensing Part

Now, one of the big things that people think about with Linux right off the bat is the licencing because people say, "Hey, it's free, it's free, it's free." Okay, so let's talk about software licensing. There is, of course, the idea of the closed source license, which is similar to most of the operating systems that you see. That is, you purchase the software rather than downloading it illegally from BitTorrent. You buy it and they give you the right to use it, but you can't distribute it. You can't modify or reverse engineer the software. Now, modify does not mean adding new programs to the operating system; modify actually means changing the kernel or how the operating system behaves. An open source licence means it's free to use modify and you can distribute it as long as you stay within the terms of the licence or what they call the new PublicLicense or some people call it the new Public License. I say the Ganu. So you can hear the GNU part of this. But anyway, the GPL is the abbreviation for that whole thing, the Public License. And that may have some rules about what you cannot do to violate an open source. For example, if you add some sort of closed source application to an open source program, that might violate the GPL because you can't really distribute something that's open source that's relying on a closed source program. So those are things you have to deal with when you're looking at the GPL. Now there is the LGPL, which is kind of a middle man, if you will, between the open source and the closed source. That's where we'd say it sits, somewhere between the GPL and the more restrictive or permissive license models, as I just described. But it's one way we can use it as a method to mix different types of licensing, especially when it comes to our trying to distribute software, and that's a big deal. As an example, if you were to write a programme that helps draw a box on the screen and that's licenced to you and you want people to pay for it, can I really include it in my distribution, in my open source distribution, if it's closed source? Well, we can alter our work with the licencing to be able to say, yes, I can distribute this to a point. But I guess the main point is that open source cannot rely on closed source for functionality because doing so violates the closed source license. So, somewhere in the middle of all this wonderful legal jargon, there is the LGPL to deal with those licenses. There are also other types of licenses: MIT, Apache, and many others. Generally, they're permissive licenses, depending on the product. For example, Apache Services is naturally a part of Linux. Everybody says, "Oh, Apache Web Server, that's Linux." But Apache can run on Windows too. It is a Web service that is generally free to distribute, free to download, and free to use. That is what we would refer to as the Apache licenses.

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