RHEL 8 / CentOS 8 Linux Administration - RHCSA 8 - Class One | Mustafa Mahmoud | Skillshare

RHEL 8 / CentOS 8 Linux Administration - RHCSA 8 - Class One

Mustafa Mahmoud, Sr. Linux Admin. & Online Instructor

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15 Lessons (2h 2m)
    • 1. RHEL 8 and CentOS 8 Linux System Administration RHCSA Level I Promo Video

      2:44
    • 2. 00 Class One Overview

      3:41
    • 3. 01 Linux System Administration Introduction

      3:50
    • 4. 02 CentOS vs RHEL

      3:13
    • 5. 03 Installing Oracle VM VirtualBox

      3:29
    • 6. 04 Creating Virtual Machine

      3:18
    • 7. 05 Installing CentOS 8

      22:08
    • 8. Exercise 1 Explanation

      7:56
    • 9. 06 CentOS 8 (GNOME) GUI Skills

      16:50
    • 10. 07 Starting a Terminal Window

      5:38
    • 11. 08 Centos 8 Virtual Consoles

      3:09
    • 12. 09 The Shell Basics

      15:07
    • 13. 10 The Quick Start Commands

      15:40
    • 14. 11 The Shell Special Keys

      4:20
    • 15. Exercise 2 Explanation

      10:43

About This Class

RHEL 8 / CentOS 8 Linux Administration - RHCSA 8 - Class One

RHEL 8 / CentOS 8 Linux Administrator Essential Skills

Hi, I'm Mustafa Mahmoud. A Senior Linux Administrator and Online Instructor. I have been working as Linux System Administrator for more than ten years, currently devoted to teaching. I like to share my knowledge with others and help them advance in their careers.

Students testimonials - See what others say!

  • Siddharth Kumar: I really loved the course content and the way all details have been explained by the trainer, it will certainly help me or anyone else to improve their Linux administration skills.
  • Eric Voigt: Excellent overview of the basic skills, well organized and taught.
  • Suman Mandal: This course was useful to me. I have learned many things that were not clear to me. Thank you.

What you should know before starting

  • Basic knowledge of using a PC.

Requirements - A PC with the minimum requirement of installing RHEL 8 / CentOS 8:

  • x86_64 or ARM System
  • 2GB RAM (2GB minimum, 4GB recommended)
  • 20 GB unallocated disk space (10GB minimum, 20GB recommended)
  • Either a CD/DVD drive or a USB port for the installer media
  • Internet access is helpful

In this class you will learn:

  • Linux system administration introduction.

  • The Linux system administrator's major duties.

  • The main differences between CentOS and RHEL.

RHEL 8 / CentOS 8 Linux Administrator Essential Skills, which will include:

  • VirtualBox Download and Install.

  • Creating a CentOS 8 Virtual Machine.

  • CentOS 8 Download and Install.

  • CentOS 8 installation requirements.

  • Using Automatic Storage configuration.

  • Using  Custom Storage configuration.

  • LVM Partition scheme.

  • Adding new mount points 'partitions'.

  • The XFS file system.

  • Adjusting the resolution to view a full-resolution CentOS VM on your computer.

  • Linux system's basic modes.

  • CentOS 8 Graphical user interface.

  • Connecting to the system using graphical mode.

  • Visual overview of GNOME 3.

  • The top bar.

  • The system menu in the top bar.

  • Activities button overview.

  • Starting applications.

  • Workspaces.

  • Switching between workspaces.

  • Launching an application in a separate workspace.

  • Launching an application in a new workspace.

  • Quickly running a command.

  • Application menu.

  • Clock and calendar button.

  • New Boxes features.

  • The System menu.

  • Locking the screen.

  • Switching users.

  • Suspending the computer.

  • Powering off the computer.

  • Switching between windows.

  • The difference between terminal and shell.

  • Launching the terminal window.

  • The terminal window command prompt.

  • Checking your hostname '$HOSTNAME'.

  • Switching to root user.

  • Disconnecting from the system in graphical mode.

  • Centos 8 Virtual Consoles.

  • The text mode login screen.

  • Logging in using a virtual console.

  • The tty command.

  • The logout command.

  • The Shell Basics.

  • The bash shell.

  • The shell commands basic parts.

  • The shell alias.

  • Bash builtin commands.

  • The external commands.

  • The $PATH environmental variable.

  • The which command.

  • The echo command.

  • The env command.

  • Changing directories in the PATH variable.

  • The export command.

  • The environment configuration files.

  • The /etc/profile, /etc/bashrc, ~/.bash_profile, and ~/.bashrc files.

  • Using /etc/motd and /etc/issue files.

  • Shell commands typing rules.

  • Quick Start Commands.

  • The date command.

  • The pwd command.

  • The cd command.

  • Relative and absolute paths.

  • The passwd command.

  • The file command.

  • The head and tail commands.

  • The wc command.

  • The cat command.

  • The exit command.

  • The ls command.

  • The history command.

  • The exclamation point character ( ! ).

  • The Shell Special Keys.

RHEL 8 / CentOS 8 Linux System Administration - RHCSA 8 - Class Two

Transcripts

1. RHEL 8 and CentOS 8 Linux System Administration RHCSA Level I Promo Video: Welcome to the redhead and Reprise Lennox eight and centers it. Lennox System Administration, or HC, is a level one course where you will learn Redhead Certified System Administration level one. My name is Mustafa. I will be leading you through the course. I began my career as a network and the computer systems administrator, and it is still my current job. I have more than nine years off Lenox Operating System administration experience. I designed this course for anyone seeking to learn the Linux operating system administration efficiently. The course is intended to provide students with Lennox administration essentially skills by focusing on court administration tasks and providing knowledge for students. Blaming toe become full time landing system administrators by introducing key command line concepts and tools. By the end of the course three levels. You will be able to administrate most Lennox distributions professionally and introduce yourself as a professional ethics system administrator. Besides enjoying the Knicks features the course. Three levels will cover all the topics off the retired certified system administrator are Hcs E and Redhead served flight engineer R H C. The are hcs. They will be in two levels and are each CE will be in one level. This course includes some specific steps foreign head enterprise, Lennox it and sent to eight Lennox. But most of the content should work regardless off your Lennox distribution. Practical examples will be applied to the centers. Eight. Lennox. This content is great for learning Learning system administration from scratch. Not only I will be covering the details, but I will also practice with you using real life examples. I will walk with you through the entire process. Step by step. The ideal student for this course is anyone seeking to learn the landing system administration to improve his career or to start a new job as a professional leading system administrator. There are no requirements necessary to enroll. I only ask you to come open minded and ready to learn. Feel free to take a look at the course description, and I look forward to seeing you inside 2. 00 Class One Overview: I would hate enterprise Lennox Eat and Centers eight Lennox System Administration or HCFC Close one. This class you will learn a unique system Administration introduction The Lenox System Administrators Major Duties The main differences between centres and Redhead Enterprise Lennox It hit Enterprise Lennox Eat and Centers eight. Lending System Administrator Essential skills which will include virtual books. Download and install creating centres Aid Virtual machine centers It download and install center seat installation requirements using automatic storage configuration using custom storage configuration. Logical volume Manager Partition scheme Adding new mount Points The X fs file system Adjusting the resolution to view a folder Solution centers We em on your computer living systems Basic moods Sent US aid Graphical user interface Connecting to the system using graphical mood visual overview off Boom three. The top bar The System Menu in the top bar activities Bhutan Overview. Starting applications Workspaces Switching between workspaces. Launching an application in a separate works piece. Launching an application in a new works piece. Quickly Running acumen application menu cloak and the calendar button. New books His features. The system Menu Looking this green. Switching users suspending the computer boring off the computer switching between renders the difference between terminal and chill launching the terminal window. The terminal window command Bram it, checking your host name. Switching to root user. Disconnecting from the system in graphical mood sent to skid virtual consoles. The text wound lugging screen lugging in using a virtual console that it's you, I commend. They look outcome and the shell basics. The best show The shell commands basic parts. The Shell Alias best built in comments. The external Commins, the Beth Environment Variable the which command the Equal Kim and the M Kimmitt Changing directories in the Beth Variable. The Export Command, the Environment configuration files using off motd and issue files. Shell Payment's timing rules. Quick start Commins. The day it came in the B W. D come in the CD command relative and absolute births. The best would commend the vile command the head until commence the word Count Kim and the get command The exit Cumin, the Ellis Kim and the History Command. The exclamation point character. The Shell Special keys 3. 01 Linux System Administration Introduction: Linux System Administration Introduction Linux is an operating system or a kernel created by Linus Torvalds with other contributors. It was first released on September 17, 1991. The main advantage of Linux is that it is distributed under an open-source license which means programmers can use the Linux kernel to design their own custom operating systems. Linux is the preferred operating system for production servers and critical systems. Most Linux code is written in the C programming language. Linux has over 300 popular distributions that are being used all around the globe by users to provide their modern day computing needs and offering a variety of functions to them. The most important choices among Linux distributions are Redhat, CentOS, Fedora, Ubuntu, and Debian. Ubuntu and Debian are used by a vast majority of home or desktop users. Redhat Enterprise Linux (RHEL) and (CentOS) short for community enterprise operating system are two popular choices for servers operating system. Most of the webservers, mobile phones, personal computers, supercomputers, and cloud-servers are powered by Linux. The job of a Linux systems administrator is to manage the operations of a computer system like maintain, enhance, create user account or report, taking backups using Linux tools and command-line interface tools. Most computing devices are powered by Linux because of its high stability, high security, and open-source environment. System Administration has become a solid criterion for any organization and institute that requires a solid IT foundation. Hence, the need for efficient Linux administrators is the requirement of the time. The job profile might change from each organization as there may be added responsibilities and duties to the role. The major duties of a Linux System Administrator are: Maintain all internet requests inclusive to DNS, RADIUS, Apache, MySQL, PHP. Taking regular back up of data, create new stored procedures and listing back-up. Analyzing all error logs and fixing along with providing excellent customer support for Webhosting, ISP and LAN Customers on troubleshooting increased support troubles. Communicating with the staff, vendors, and customers in a cultivated, professional manner at all times has to be one of his characteristics. Enhance, maintain and creating the tools for the Linux environment and its users. Detecting and solving service problems ranging from disaster recovery to login problems. Installing the necessary systems and security tools. Working with the Data Network Engineer and other personnel or departments to analyze hardware requirements and makes acquiring recommendations. Troubleshoot, when the problem occurs in the server. I hope this has been informative for you and I'd like to thank you for viewing. 4. 02 CentOS vs RHEL: RHEL vs CentOS RHEL vs CentOS Red Hat Enterprise Linux is Red Hat’s official distribution. All of the Red Hat support services, SLAs (Service Level Agreements), and certifications are based on RHEL. It is intended to be an enterprise-level, stable, and secure operating system. RHEL major versions have a support cycle length of 7 years with an option to extend up to 10 years, thus being a more stable and secure operating system. Although the source code of RHEL is freely available, Red Hat restricts the redistribution of their officially supported versions of RHEL. To deploy RHEL on a server or workstation, you have to purchase a subscription from Red Hat and renew it every year except for a 30-day evaluation version. This subscription entitles you to a few additional items, such as support and patches. CentOS. CentOS is a community-developed and supported alternative to RHEL. It is similar to Red Hat Enterprise Linux but lacks the enterprise-level support. CentOS is more or less a free replacement for RHEL with few minor configuration differences. It comes with an extended support lifecycle ranging from 6 to 7 years and it can be downloaded directly from the official website. CentOS does tend to run a little behind RHEL with releases. Minor releases can take hours or days to be deployed, and for major releases, it can be several months. It might seem like an insignificant disadvantage, having in mind that you get CentOS for free, but for companies that think in terms of multiple-year lifespans for their servers and software, the difference can be trivial. An important difference between RHEL and CentOS is access to repositories. A repository is the installation source used for installing software. If you are using free software such as CentOS, correct repositories are automatically set up, and no further action is required. If you are using Red Hat Enterprise Linux with a subscription, you’ll get access to the Red Hat repositories on the Red Hat Network. In this course. I will use CentOS 8 as it offers all features needed that RHEL 8 offers without paying for it. I hope this has been informative for you and I'd like to thank you for viewing. 5. 03 Installing Oracle VM VirtualBox: Now I will give you a short description about VirtualBox, and then I will show you how to download and install VirtualBox on your machine. Oracle VM Virtual Box is a free and open source hypervisor for X86 computers, currently being developed by Oracle Corporation. Virtual books may be installed on a number of host operating systems, including Linux, Mac OS, Windows, Solaris, and open Solaris. It's aborted the creation and management of the disk virtual machines running versions and the deviations of Windows, Linux, BSD, Solaris and others, and the limited visualization of MacOS guests on Apple hardware. For some guest operating systems, I guess the addition baggage of device drivers and system applications is available, which typically improves performance, especially of graphics. Go to the Visual Books website. Go to the download section. There are versions available for Windows, Mac and Linux. Download the Windows version at the top by clicking windows hosts. If your host operating system is Mac OS X, then you will click on Mac OS X hosts to download the.dmg file. And after finishing the unloading of in the file and follow the steps you'd see. Vet to Windows users. Start the installation. Resnik is to continue the setup wizard. Choose not to install USB support or by phone support. Do this by clicking the gray icon near each option and select the red X entire feature would be unavailable, leaving the VirtualBox networking rigid and host only enabled. Then click Next to continue. If this is your first time dealing with virtual machines, this would eliminate the need to uninstall custom drivers, which makes installing and uninstalling virtual Books easier. If you have working with virtual machines before, you can choose to keep this option selected. I'll check the default settings if you don't wish virtual books icons to appear on the desktop or that quick launch bar. However, keep the register file association books that chicken. This will ensure that files associated with virtual books open only with VirtualBox. Then Risk Next. Click Yes to proceed with installation. Click Mr. click finish to start the virtual books. I hope this has been informative for you and I'd like to thank you for viewing. 6. 04 Creating Virtual Machine: Creating a CentOS Virtual Machine. Click the “New” button to start the virtual machine wizard. Give your virtual machine a name “If you give it CentOS”, The version will automatically default Type to Linux and Version to Red Hat Then click “Next”. Select the amount of memory your Virtual Machine will use. When we choose the operating system in the previous step, VirtualBox automatically recommends the proper amount of memory to use. The Recommended value is 1 GB if the machine RAM is 4 GB. 2 GB if the machine RAM is 8 GB. Note that, using RAM lower than 4 GB is not recommended. For headless servers, 1 GB is enough. For server with graphical user interface, it should be at least 2GB. Here you can choose 2GB or more then Press Next. Now select ‘create a new virtual hard disk’, then click “Create”. This opens a second wizard to create a new virtual hard disk, choose “VDI”. VDI is a virtual drive format used by Oracle VM VirtualBox. Click 'Next' select either "Fixed-Size Storage" or "Dynamically Expanding Storage" depending upon your needs. Fixed-Size storage is going to be the size of the virtual hard disk on the host Operating System for example a virtual disk 20 GB will be 20 GB on the host Operating System's hard disk. A dynamically expanding storage will be only the size of CentOS on your hard disk but will grow in size as files are added to it until it reaches its limit. Select dynamically allocate memory. Click 'Next'. Selection of memory size 20 G.B. or more is recommended. Select the size of the virtual hard disk to be 20 G.B. Click Create. Now you should see your CentOS virtual machine in the list. I hope this has been informative for you and I like to thank you for viewing. 7. 05 Installing CentOS 8: To download the centers it iso file. Go to the official website. Click on CentOS Linux DVD, ISO button. Click on the Miro link that is geographically closer to you. Your browser should start downloading the sense it iso installation image. It may take a while for the download to complete. After the sense it iso file is downloaded. Centers can be installed on physical as well as virtual hardware. First, installing centers physically. And this can be done using installation DVD or Habitable centers, USB. Creating a mutable centers USB stick from Microsoft Windows is very symbol and we are going to cover the process in the next few steps. You will need a GB or larger USB stick drive. Microsoft Windows seven or later. Rufus, which is a free and open source USB stick writing tool. Go to the Google search type Rufus, goto, the Rufus website. Click the download button. After the download is complete. Performed the following to configure your USB device in Rufus. Lunch, Rufus. Insert your USB stick. Rufus will update to set the device within the device field. If the device is incorrect, select the correct one from the device fields drop-down menu. To select the centers it iso file. Click select alongside the enabled create habitable desk using ISO image. This will open a file requester from which you can navigate to and select the ISO file. For best computability with newer hardware, keep the partition scheme and target system typeset as master boot record, MBR, unified Extensible Firmware Interface, UEFA. Leave all other parameters with their default values and click Start to initiate the writing process. If you are asking that there are files needed to be downloaded, agreed for the download. If this error a beers with you, follow these steps. Click the OK button. From the event log. Can be that the alluding address. Open Internet Explorer. In the address bar based the cabinet address. Then press enter. As you can see, to access this address, we need to turn on TLS 1.11.2. Click on the Change settings, find TLS. Click on the three TLS checkboxes. Then click OK. Now clues the Internet Explorer and try again. Click Start. Agreed for the download. You will be then alerted that Rufus has detected that the centers ISO is an iso hybrid image. This means the same image file can be used as the source for both additivity and a USB stick without requiring conversion. Key bright in ISO image mood selected, and click on OK to continue. Rufus would warn you that all data on your selected USB device is about to be destroyed. This is a good moment to double-check. You have selected the correct device before clicking OK. After checking, click okey. The ISO will now be written to your USB stick. And that progress bar in Rufus will give you some indication of how long this will take. With a reasonably modern machine. This should take around three minutes. Rufus will complete the writing process and silently drop back to its default window. Congratulations, you now have centered it on a USB stick, potable and ready to go. Once you set up your USB drive to be potable with centers, you can then reboot your system, Catch the boot menu, and boot from USP. If your computer doesn't automatically put from the USP, try holding F2 when your computer first starts. With most machines, this will allow you to select the USB advice from a system specific boot menu. It will lead you run a fully usable live CD version of centers it. Second, installing centers it using VirtualBox. Now, we will install sense it using virtual box. We will do this to keep your old breathing system as it is. So you can switch back to your old operating system anytime you want without any difficulties. And if you want to install sensors it directly to your machine, there is no problem. You can follow the same steps. Centers it installation requirements. A system with a minimum 20 GB of hard disk, two GB of RAM, and a good internet connection. Start VirtualBox. Select your centers virtual machine. Once you have done this, click the Settings spot-on. Click storage step. Click on Controller IDE, Ed's optical drive. Then press choose this proton to choose centers it iso file. Then press urban centers I x2 will be mounted under controller device. Click on the System tab on the left. Choose put order, and keep Optical on the top as the first periodicity. Press OK, to return to the main window. Your sentence machine is ready to boot now. To install since it select your virtual machine. Then click the start button. Centers Virtual Machine will start in a separate window. And you should see the grub boot menu. From this menu, you can choose from different options. Install centrist eight. Choose this for a normal installation. This, this media and install centers eat. Select this if you want to test the installation media before installing. Notice that this will take a significant amount of time. Troubleshooting. Select this option for some troubleshooting options. This option is useful if you cannot normally boot from your computer's hard drive anymore. Select Install centers, legs it from the graph menu and press enter. Choose your preferred language and click on continue. From here, you can set keyboard and installation source, software selection, type, kingdom, and installation destination. Now click on the installation destination. Select the virtual hard drive. For GNU Linux users. Click on the chosen local hard drive. Then select Automatic from storage configuration section. And click on Done. For more advanced users. You can select Custom from storage configuration section. The mixture that desk you want to use a selected and click Done to proceed. Choose LLVM partition scheme. Then click the plus sign to add new mount point. Llvm is short for Logical Volume Management. You can think of logical volumes as dynamic partitions, meaning that you can create, Resize, Delete LLVM partitions from the command line while your Linux system is running without needing to reboot the system to make the kernel aware of the newly created or resized partitions. Setting up the environment that is required in this course, I recommend using the following disclaimer out. Based on a Twinkie GB hard disk, you will need to configure a foreign sludge Boot partition size of 500 MB. Then click add mount point. And the device type choose Standard. And under File System choose x fs file system. Then click on update settings. The NFS file system is a highly scalable, high-performance file system that supports file system up to 16 byte, approximately 16 billion GB, files up to eight byte, approximately 8 billion GB. And directory structures containing tens of millions of entries. X fs supports metadata journalling, which facilitates quicker crash recovery. The NFS file system can also be the fragmented and resized while mounted and active. This file system is selected by default and is highly recommended. Click the plus sign to add new mount point forward slash for root partition with a size of ten GB. Think click, Add mount point button, and advice type choose LLVM. And under File System choose x fs formatted Logical Volume. Click the plus sign to add new mount points WEB with a size of 1GB logical volume that is used as swept species. Then click add marked point button. And the device type choose LLVM. And under File System choose swept. Click the plus sign to add new mount point slash home for the user home partition. Here, I will leave the desire to travesty blank to take all their meaning size from the 20 GB. Then click add mount point button. Under Device Type, Choose LLVM. And under File System choose x, fs. Now click on the Done button. You will see a summary of the changes we have made. Chick the summary, then click the accepted Changes button to write your configuration. Now click on network and host name. It is off by default. Switch it on. Type in the hostname and click on apply. Then click on done. If you want to install, since it's a river with graphical user interface, then you don't have to do anything else. But if you want to install since it headless server thing, click on software selection. Then select server and click on Done. But here, we will leave it with the graphical user interface. If you want to set up your time Xun, click on time and did. Select your region and city. And click on done. Now to configure Kingdom. Kingdom is used to set up a process that is started with your server to allow you to create a memory cool damping case, the kernel crashes. If your server does have enough RAM available, that will result in keydown being active automatically. If your server is low on memory, you won't have it running by default. As Linux kernel crashes don't occur very frequently and S sitting up kingdom is not apart of the ROHC or our MHC-II objectives. You can just disable kingdom and click that button. Once you are done, click on begin installation. The installation should start. Now you have to enter the root password. Click on the root password button. Type u root password. Confirm it. Click on done. Now to create a new login user. Click on User creation. Type in the new user personal information. You can check the mic, this user administrator checkbox to make this user administrator. But here, I need a normal user because logging in with administrator privileges has a lot of risks. So we will need a regular user while using the system in normal tasks. Type the new user password. Confirm it. Link click on done. Once the installation is complete, click on reboot. Virtualbox Virtual Machine may put from the sentence it installation DVD. Again. To avoid that, click on devices. Choose optical drives. The choose remove disc from virtual drive. Click on force amount. Now, click on machine. Choose reset. To reset the virtual machine. Click on reset to confirm the action. The virtual machine should boot from the virtual hard drives. One sentence, it boots. We will complete the initial setup. Click on license not accepted. Read the license, then check the I accept the license agreement. Checkbox. Then click done. Click Finish configuration. You can login using the username and password that you have set during the installation. Click on the username, typed the password, then press enter, or click on the Sign In button. Now, the genome initial setup wizard will open. Choose your preferred language than breast. Next. Select your keyboard layout than breast. Next. Choose to let applications access your location or not. The embrace. Next. You can connect with your online accounts or presses, skip. Presses, start to start using centers. It they're getting starting guide will open. You can preview it if you wish or close this window. Steps for adjusting the resolution to view a full resolution centers virtual machine on your computer. Click the System menu in the top right corner to manage your system settings. Click on the System Settings icon. Click on the icon, finds plays, and click on it. Choose the suitable resolution for your screen. Then click the Apply button. Click the Q Changes button. Now you are viewing a full resolution centers it virtual machine on your computer. I hope this has been informative for you and I'd like to thank you for viewing. 8. Exercise 1 Explanation: Search for synthesis website. Select the download section. Now look at the sentence eight Linux ISO file. Start Virtual Box. Period, your new sentence it virtual machine. Using the sentence it minimum requirements. Select your new virtual machine, then click on the Settings button. Select the storage step. Under Controller IDE at the sentence it iss image. After that, select the system tap, chick, that optical is the Paris superiority. And the change the pointing device to you speed tablet to ensure that your mouse would vote without problems. Click OK to save the configuration. With your virtual machine selected. Click the start button. Select installed centers it Linux. Then press Enter. Choose your preferred language and click Continue. Click on software selection. Select server with GUI, and click on done. Select Installation destination. Select your hard disk, then select custom storage configuration. Click done. Select the LLVM partitioning scheme. Then click the plus sign to add the specified mound pointers with their values. Now click done. Check the summary of the changes. Then click exempted changes. Click on Network and hostname. Switches on the n-type you new hostname. Click on, Apply. Click Done. Click on time. Indeed. Select your region and current city. Then click Done. Click on kingdom. I check the enabled kingdom checkbox. Then click done. Click on begin installation to start the installation. Click on root password to set the root password, type u root password. Confirm it. Click on done. Now to create a new user test, click on User creation. Type their username, typed the password, confirm the password. Then click on done. Thanks for viewing. 9. 06 CentOS 8 (GNOME) GUI Skills: CentOs 8 Graphical user interface. To work on a Linux system directly, you will need to provide a username and password. Linux systems have two basic modes for a system to run in: either quick and sober in text console mode, which looks like DOS with mouse, multitasking, and multi-user features, or in graphical mode, which looks better but eats more system resources. Here, The default graphical mode of the CentOS 8 desktop environment is GNOME 3.28. The graphical mode is the default nowadays on most desktop computers. You know you will connect to the system using graphical mode when you are asked for your username and password. To log in, click on your username and enter your password to the system and click OK or press Enter. It can take a little while before the graphical environment is started, depending on the CPU speed of your computer, the software you use, and your personal settings. It is generally considered a bad idea to connect (graphically) using the root username, Which is the system administrator’s account, since the use of graphics includes running a lot of extra programs, in root's case with a lot of extra permissions. So to keep all risks as low as possible, use a normal user account to connect graphically. But there are enough risks to keep this in mind as a general advice, for all use of the root account: only log in as root when extra privileges are required. CentOS 8 GNOME 3 overview. GNOME is a free and open-source desktop environment for Unix like operating systems. The GNOME 3 features a completely reimagined user interface designed to stay out of your way, minimize distractions, and help you get things done. When you first log in, you will see an empty desktop and the top bar. The top bar provides access to your windows and applications, your calendar and appointments, and system properties like sound, networking, and power. In the system menu in the top bar, you can change the volume or screen brightness, edit your Wi-Fi connection details, check your battery status, log out or switch users, and turn off your computer. To access your windows and applications, click the Activities button, or just move your mouse pointer to the top-left corner. You can also press the Super key on your keyboard. You can see your windows and applications in the overview. Also, you can just start typing to search your applications, files, folders, and the web. On the left of the overview, you will find the dash. The dash shows you your favorite and running applications. Click any icon in the dash to open that application; if the application is already running, It will be highlighted. Clicking its icon will bring up the most recently used window. You can also drag the icon to the overview, or onto any workspace on the right. Right-clicking the icon displays a menu that allows you to pick any window in a running application, or to open a new window. You can also click the icon while holding down Ctrl to open a new window. When you enter the overview, you will initially be in the windows overview. This shows you live thumbnails of all the windows on the current workspace. Click the grid button at the bottom of the dash to display the applications overview. This shows you all the applications installed on your computer. Click any application to run it, or drag an application to the overview or onto a workspace thumbnail. You can also drag an application onto the dash to make it a favorite. Your favorite applications stay in the dash even when they’re not running, so you can access them quickly. There are several ways of opening an application once you’re in the Activities overview. Start typing the name of an application and you will notice that searching begins instantly. If this doesn't happen, click the search bar at the top of the screen and start typing. If you don’t know the exact name of an application, try to type a related term. If you click the grid button at the bottom of the dash. You will see the frequently used applications if the Frequent view is enabled. If you want to run a new application, press the All button at the bottom to view all the applications. Then press on the application to start it. Workspaces. Workspaces are separate desktop screens which have different application windows. These can be used to organize the working environment by grouping open application windows by task. For example, windows being used to perform a particular system maintenance activity (such as setting up a new remote server) can be grouped in one workspace, while email and other communication applications can be grouped in an other workspace. There are three methods for switching between workspaces. One method is to click the indicator in the right corner of the window list and select the desired workspace. Another, perhaps the fastest, is to type Ctrl+Alt+UpArrow or Ctrl+Alt+DownArrow to switch between workspaces sequentially. A third is to switch to the Activities Overview and click the desired workspace. You can launch an application in a separate workspace by dragging its icon from the dash, and dropping it onto one of the workspaces on the right-hand side of the screen. The application will open in the chosen workspace. Also, you can launch an application in a new workspace by dragging its icon to the empty workspace at the bottom of the workspace switcher or to the small gap between two work spaces Another fast way of launching an application is to press Alt+F2 then enters its command name and then press the Entre key. Here, the name of the app is the command to launch It. You Can Use the arrow keys to quickly access previously run commands. Application menu The application menu, located beside the Activities button, shows the name of the active application alongside with its icon and provides quick access to windows and details of the application, as well as a quit item. Clock, calendar & appointments You can click the clock on the top bar to see the current date, a month-by-month calendar, a list of your upcoming appointments and the new notifications. You can also open the calendar by pressing Super+M together. You can access the date and time settings and open your full Evolution calendar directly from the menu. New Boxes Features Boxes, the GNOME application for using remote and virtual machines, has a number of new features and enhancements for GNOME 3.28. One major new feature is automatic downloading of operating systems, straight from the new box assistant. To create a virtual machine, all you have to do is pick the operating system you want to use, and Boxes will do the rest. The new version of Boxes also makes it easy to transfer files between your computer and virtual machines. To transfer files, you can either drag and drop them on to the Boxes window, or select the Send Files option and select files to be transferred using a file chooser. In both cases, Boxes provides feedback about the progress of file transfers, so you know how long they are going to take, as well as when they have finished. The system menu. Click the system menu in the top-right corner to manage your system settings and your computer. When you leave your computer, you can lock your screen to prevent other people from using it. You can also quickly switch users without logging out completely to give somebody else access to the computer, or you can suspend or power off the computer from the menu. If you have a screen that supports vertical or horizontal rotation, you can quickly rotate the screen from the system menu. If your screen does not support rotation, you will not see the button. When you lock your screen, or it locks automatically, the lock screen is displayed. In addition to protecting your desktop while you’re away from your computer, the lock screen displays the date and time. It also shows information about your battery and network status. Switch between windows You can see all the running applications that have a graphical user interface in the window switcher. This makes switching between tasks a single-step process and provides a full picture of which applications are running. From a workspace press Super+Tab to bring up the window switcher. Release Super to select the next (highlighted) window in the switcher. Otherwise, still holding down the Super key, press Tab to cycle through the list of open windows, or Shift+Tab to cycle backwards. You can also move between the application icons in the window switcher with the right or left keys, or select one by clicking it with the mouse. Previews of applications with a single-window can be displayed with the down arrow key. From the Activities overview, click on a window to switch to it and leave the overview. If you have multiple workspaces open, you can click on each workspace to view the open windows on each workspace. I hope this has been informative for you and I'd like to thank you for viewing. 10. 07 Starting a Terminal Window: Starting the terminal window. Before starting I would like you to know the difference between the terminal and the shell. The terminal refers to a wrapper program which runs a shell. While the shell is the program which actually processes commands and returns the output. to launch the terminal window click on activities and in the search bar type terminal. Then click on the terminal icon. Or click on activities choose terminal. if appear or click on activities then click on Show applications then click on all, and from Utilities click on terminal. The terminal window is your control panel for the system. Almost everything that follows is done using this simple but powerful text tool. A terminal window should always show a command prompt when you open it. Once you launch the Terminal, you would find something as ([email protected]:~$) ([email protected]:~$) written on it. The first part of this line ‘mo’ is the name of the user. The second part (my.centos.server) is the computer name or the hostname which we added during the installation. The hostname helps identify a computer over the network. In a server environment, the host-name becomes important. You can use this command to check your hostname (echo $HOSTNAME) (echo $HOSTNAME) The tilde '~' sign shows that the user is working in the home directory, you can check using the pwd command. If you change the directory this sign will vanish. For example, if we moved from the mo /home directory to /bin using the 'cd' command. The ‘~’ sign will be changed with the current directory name. It will appear again when moving back to the home directory either by using the command cd /home/username cd /home/username or by typing the command cd only or by typing the command cd ~ and pressing Enter. The '$' sign suggests that you are working as a regular or standard user. While working as a root user by typing the ‘su –‘ ‘su –‘ command and pressing enter followed by the root password the '#' will be displayed and the username will be changed to root. To disconnect from the system in graphical mode, you need to close all terminal windows and other applications. After that Click the system menu in the top-right corner then hit the power button and choose either to reboot or to shutdown the system as needed. Or click on the username then click on logout. Closing everything is not really necessary, and the system can do this for you, but session management might put all currently open applications back on your screen when you connect again. When you see the login screen again, asking to choose a username, then logout was successful. I hope this has been informative for you and I'd like to thank you for viewing. 11. 08 Centos 8 Virtual Consoles: CentOS Virtual Consoles. A virtual console is a text console. You can use a terminal window to issue shell commands. However, you can issue shell commands even when X is not running or available using the Linux virtual console. Linux provides six virtual consoles for interactive use; the first and second virtual consoles are associated with the graphical user interface. You can use special keystrokes to switch between virtual consoles. With a graphical environment running, access a text login prompt on a virtual console by holding Ctrl+Alt and pressing a function key (from F3 to F6). You can view only a single console at a time, but you can switch rapidly between consoles by using the appropriate keystroke. A text-mode login screen typically shows some information about the machine you are working on, the name of the machine and a prompt waiting for you to log in. To log in using a virtual console, type your user name and press Enter. The system will prompt you for the password associated with your account. Type your password and press Enter. To prevent anyone nearby from learning your password, Linux does not display your password as you enter it. If you suspect you’ve typed it incorrectly, you can either hit the Backspace key several times sufficient to delete the characters you’ve entered. When the system has accepted you as a valid user you will be given a shell, indicated with the same prompt that you would get in graphical mode. Also in text mode: log in as root only to do setup and configuration that requires administrator administrator privileges, such as adding users, installing software packages, and performing network and other system configuration. Once you are finished, immediately leave the special account and resume your work as a regular user. You can check the terminal you are connected to using the tty command. Logging out is done by entering the logout command, followed by Enter. You are successfully disconnected from the system when you see the login screen again. You can press Ctrl+Alt+F1 or F2 to return back to the graphical desktop. I hope this has been informative for you and I like to thank you for viewing. 12. 09 The Shell Basics: The Shell Basics The shell is the default working environment for a Linux administrator It is the command interpreter in any Linux operating system The Shell is a program that executes other programs. It provides the computer user an interface to the Linux operating system so that the user can run different commands or tools with some input data When the shell has finished executing a program, it sends an output to the user on the screen, which is the standard output device. For this reason, it is referred to as the “command interpreter” The shell is much more than just a command interpreter. It is also a programming language of its own with complete programming language constructs such as conditional execution, loops, variables, functions and many more. That's why the GNU Linux shell is more powerful compared to the Windows shell. Different shells for Linux are available, but bash is the common shell So when we are talking about “the shell” in this course, we are talking about the bash shell Bash stands for Bourne Again Shell and it is the default shell on many Linux distributions today It is also a Bourne shell compatible shell and offers practical improvements over the Bourne shell for programming and interactive use which includes command-line editing, Job Control, Unlimited size command history, Shell Functions and Aliases, Unlimited size Indexed arrays, Integer arithmetic in any base from two to sixty-four. Commands entered at the shell prompt have three basic parts Command to run, options to adjust the behavior of the command, arguments which are typically targets of the command The command is the name of the program to run. It may be followed by one or more options, which adjust the behavior of the command or what it will do Options normally start with one or two dashes to distinguish them from arguments Commands may also be followed by one or more arguments, which often indicate a target that the command should operate on The shell makes a difference between three kinds of commands. Aliases, internal commands, and External commands A shell alias is a shortcut to reference a command It can be used to avoid typing long commands. For common patterns it can reduce keystrokes and improve efficiency A simple example is setting default options on commands to avoid having to type them each time a command is run. Some aliases are provided by default; type alias on the command line to get an overview To define an alias. use "alias newcommand=oldcommand" "alias newcommand=oldcommand" "alias newcommand=oldcommand" "alias newcommand=oldcommand" as in the default "alias ll=ls -l --color=auto" Note that, aliases are executed before anything else Second Bash builtin commands. Also known as internal commands, are part of the shell itself Each builtin command is executed directly in the shell itself, instead of an external program which the bash would load and run You can show the list of built in commands using the help command An example of the internal or builtin command is alias command while the top command is an example of the external command To find out whether a given command is an internal builtin or external, you can use the type command For example type -a cd type -a cd type -a cd type -a top The $PATH is an environmental variable in Linux and other Unix like operating systems that tells the shell which directories the executable programs are located when a user enters a command To find out which exact command the shell will be using, you can use the which command. For instance, type which ls which ls to find out where the shell will get the ls command from You can use the ‘echo’ command to show the contents of the $PATH variable by typing echo $PATH echo $PATH Which reads the current value of the PATH variable and prints that on the standard output (STDOUT) Also, you can get an overview of the current variables defined in your shell environment, by typing the env command When you want the system to execute a command, you rarely have to give the full path to that command For example, we know that the ls command is in the /bin directory You can check with which ls which ls Yet we don't have to enter the command /bin/ls for the computer to list the content of the current directory, the PATH environment variable takes care of this This variable lists those directories in the system where executable files can be found and thus saves the user a lot of typing and memorizing locations of commands So the path naturally contains a lot of directories containing bin somewhere in their names, to check type echo $PATH As soon as a match is found, the search is stopped, even if not every directory in the path has been searched If you use programs in other directories more frequently, you can change your path to look in your directories, for example, to add your /home/Downloads directory, You can use the export commands export PATH= export PATH= export PATH= We will enter the old PATH data followed by :/home/Downloads :/home/Downloads then press Enter Note that here changes are not permanent When using the export command in a shell, the changes are temporary and only valid for this session Opening new sessions, even while the current one is still running, will not result in a new path in the new session To make it permanent, you need to add the export PATH command to your home/mo/.profile file or home/mo/.bashrc file For example, to add home/Downloads to the PATH variable in the home/mo/.bashrc Here, I will use the Nano editor to open the .bashrc file for editing. nano .bashrc nano .bashrc Press Enter At the end of this file add export PATH=$PATH:/home/Downloads export PATH=$PATH:/home/Downloads export PATH=$PATH:/home/Downloads export PATH=$PATH:/home/Downloads export PATH=$PATH:/home/Downloads export PATH=$PATH:/home/Downloads Here, I put $PATH to keep the old PATH as it is or it will be removed and you will only see the /home/Downloads PATH Press Ctrl+X Then press Y to confirm saving, and press Enter to confirm using the same name and exit Note that, this will not automatically update your PATH for the remainder of the session to do this, you should run source /the path to the .bashrc file source /the path to the .bashrc file or source .bashrc file if you are in the same directory and press Enter Let's check echo $PATH echo $PATH Note that, for the root user, you will do the same steps but on the /etc/profile file or the /etc/bashrc file Environment Configuration Files When a user logs in, an environment is created for that user automatically. This happens based on four different files where some script code can be specified and where variables can be defined for use by one specific user /etc/profile file This is the generic file that is processed by all users upon login /etc/bashrc file This file is processed when subshells are started User home directory (~) "~/.bash_profile" ~/.bash_profile in the user home directory. In this file, user-specific login shell variables can be defined And .bashrc file in the user home directory, in this user-specific file, subshell variables can be defined In these files, a difference is made between a login shell and a subshell. A login shell is the first shell that is opened for a user after the user has logged in From the login shell, a user may run scripts, which will start a subshell of that login shell Using /etc/motd file and /etc/issue file Bash offers an option to include messages in the /etc/motd and the /etc/issue files Messages in /etc/motd display after a user has successfully logged into a shell. Notice that users in a graphical environment do not see its contents after a graphical login. Using /etc/motd can be a convenient way for system administrators to inform users Another way to send information to users is by using /etc/issue file. The contents of this file displayed before the user logs in This provides an excellent means of specifying specific login instructions to users who aren't logged in yet using text user interface. For example nano /etc/issue nano /etc/issue nano /etc/issue Add some data Press Ctrl+X. Then press Y to confirm saving. And press Enter to confirm using the same name and exit Now Press Ctrl+Alt+F3 As you can see, the data I have entered is appearing up I hope this has been informative for you, and I would like to thank you for viewing. 13. 10 The Quick Start Commands: The Quick Start Commands Each string typed into the shell can have up to three parts the command, options (that begin with a - or --), and arguments. Each word typed into the shell is separated from each other with spaces. Commands are the names of programs that are installed on the system. Each command has its options and arguments. The Enter key is pressed when a user is ready to execute a command. Each command is typed on a separate line and the output from each command displays before the shell displays a prompt. If a user wants to type more than one command on a single line, a semicolon (;), can be used as a command separator. A semicolon is a member of a class of characters called meta-characters that has special meanings for bash After launching the terminal: Now we will have a look at the Quickstart commands. The date command is used to display the current date and time. Type date Then press Enter. The date command can also be used by the super-user to set the system clock. An argument that begins with a plus sign (+) specifies a format string for the date command. For example, we use the command ( date +%R ) to show the time formatted hour:minutes hour:minutes And we use the command ( date +%x ) ( date +%x ) to show the date formatted month/day/year. The pwd command ( print working directory ), used for displaying the current working directory. the cd command ( change directory ), used for changing directories type ( cd / ) to move to the root directory. It is important to not forget space between cd and /. Otherwise you will get an error. The root of the file system in Linux is denoted by '/'. Similar to 'c:\' in Windows, Note that, in Windows, you use backward slash "\" while in Linux system, the forward slash is used "/". You can navigate through multiple directories at the same time by specifying its complete path. For Example, If you want to move to the cpu directory under /dev directory, we do not need to break this operation into two parts. Instead, we can type 'cd /dev/cpu' to reach the directory directly. For navigating up one directory level, we can use 'cd ..'. we can check using the pwd command. Here, by using the 'cd ..' command, we have moved up one directory from '/dev/cpu' to '/dev' directory. Then by again using the same command, we have jumped from '/dev' to '/' root directory. Relative and Absolute Paths. A path in computing is the address of a file or folder. For Example, /home/mo/Downloads This is the path for the Downloads directory. There are two kinds of paths. First Absolute Path. Let's say you have to browse the images stored in the Pictures directory of the /home/mo /home/mo.The absolute file path of Pictures directory is /home/mo/Pictures.To navigate to this directory, you can use the command cd /home/mo/Pictures cd /home/mo/Pictures This is called absolute path as you are specifying the full path to reach the file. Second Relative Path. The relative path comes in handy when you have to browse another subdirectory within a given directory. It saves you from the effort to type complete paths all the time. Suppose you are currently in your Home directory ‘cd /home/mo’. You want to navigate to the Downloads directory. You don’t need to type the absolute path 'cd /home/mo/Downloads'. Instead, you can simply type 'cd Downloads' and you would navigate to the Downloads directory as you are already present within the '/home/mo' directory. This way you do not have to specify the complete path to reach a specific location within the same directory in the file system. The passwd command changes a user's password. The original password for the account must be specified before a change will be allowed. By default, passwd is configured to require a strong password, consisting of lowercase letters, uppercase letters, numbers, and symbols, and is not based on a dictionary word. Note that, the super-user can use the passwd command to change other users' passwords. For example, to change my password as user mo type passwd and press enter. First, I will need to enter the old password then the new password and again retype the new password. And as the root user to change the user mo password type the command "passwd mo". Linux does not require filename extensions to classify files by type. The file command scans the beginning of a file's contents and displays what type it is. The files to be classified are passed as arguments to the command. For example, file /etc/passwd file /etc/passwd Another example, file /home file /home The head and tail commands display the beginning and end of a file respectively. By default, these commands display 10 lines, but they both have a ( -n ) option that allows a different number of lines to be specified. The file to display is passed as an argument to these commands. For example, head /etc/passwd And to show the last 3 lines in the passwd file you can use the command tail -n3 /etc/passwd tail -n3 /etc/passwd tail -n3 /etc/passwd Or you can type tail -3 /etc/passwd tail -3 /etc/passwd The wc command counts lines, words, and characters in a file. It can take a ( -l, -w, or -c ) ( -l, -w, or -c ) option to display only the lines, words, or characters, respectively. For example, wc /etc/passwd And to show the number of lines only wc- l /etc/passwd wc- l /etc/passwd And to show the number of characters in two files and the total of the characters in the two files wc -c /etc/group /etc/hosts wc -c /etc/group /etc/hosts The cat command throws the content of any textfile on the screen. For example, cat etc/hosts cat etc/hosts cat etc/hosts The exit command is used to leave this session. The ls command is used to list the specified directory content. An example is ls /etc, where the directory /etc is the argument to the ls command. This indicates that you want to see the content of that directory, instead of the default, which would be the content of the current directory, obtained by just typing ls followed by Enter. Some commands require arguments, sometimes arguments are optional. You can find out whether a command takes options and arguments, and which ones are valid, by checking the online help for that command, which we will discuss later. The history command displays a list of previously executed commands prefixed with a command number. The exclamation point character ( ! ), is a metacharacter that is used to expand previous commands without having to retype them. ! ( ! ) Sign followed by number expands to the common matching the number specified. ( ! ) followed by string expands to the most recent command that begins with the string specified. For example, Or you can redo a command that was done before by specifying it’s number from the history after the exclamation mark, For example, history then choose a command and specify its number. Now to redo it. Enter the exclamation mark followed by the number and press Enter. The arrow keys can be used to navigate through previous command lines in the shell's history. Up Arrow edits the previous command in the history list. Down Arrow edits the next command in the history list. Use this key when the Up Arrow has been pressed too many times. Left Arrow and Right Arrow move the cursor left and right in the current command line being edited. I hope this has been informative for you, and I'd like to thank you for viewing. 14. 11 The Shell Special Keys: The shell special keys Using Bash features, Several special key combinations allow you to do things easier and faster with the GNU shell, Bash, which is the default on almost any Linux system. You are strongly suggested to make a habit out of using them, so as to get the most out of your Linux experience from the very beginning. Now, let's try some examples. Press Ctrl+A to Move the cursor to the beginning of the command line. Press Ctrl+C to End a running program and return the prompt. Press Ctrl+D to Log out of the current shell session, it is equal to typing exit, and if you and if you are using the root user it will switch to the regular user. Press Ctrl+E to Move the cursor to the end of the command line. Press Ctrl+H to Generate backspace character. Press Ctrl+u Clear from the cursor to the beginning of the command line. Press Ctrl+k Clear from the cursor to the end of the command line. Press Ctrl+L to clear this terminal. Press Ctrl+R to Search in command history for a particular command. Press ArrowLeft or ArrowRight to move the cursor one place to the left or right on the command line, so that you can insert characters at other places than just at the beginning and the end. Press ArrowUp or ArrowDown to Browse history. Go to the line that you want to repeat, edit details if necessary, and press Enter to save time. Press Shift+PageUp or Shift+PageDown to browse the terminal buffer to see text that has scrolled off the screen. For example cat /etc/passwd cat /etc/passwd and try shift page up or shift page down Tab completion allows a user to quickly complete commands or file names once they have typed enough at the prompt to make it unique. for example, enter "ec" and press the Tab to complete the command If the characters typed are not unique, pressing the Tab key twice displays all commands that begin with the characters already typed. for example, enter "pas" enter "pas" and press the Tab twice The result will be as you can see, then you can choose the best choice for you or the required choice. I hope this has been informative for you, and I would like to thank you for viewing. 15. Exercise 2 Explanation: Start working on the system. You will need to login to the user. Type the user password. Press Enter. Let's solve the exercise points one by one. The exercise GUI section explanation. To launch the num help Jeff Kelley press F2, type Yelp. Then press enter. To open a terminal window. Click on activities. Then click on terminal. Also, you can add a shortcut to easily append the terminal by doing the following. Right-click. Choose Settings. Click on devices. Choose keyboard, press the edX sign. In Nim type terminal, and in command type terminal. Clicks it shortcut. You can choose your preferred keystroke. I recommend choosing control. Lt is the shortcut, is the report on other Linux distributions like now, click close this window. Now you can try the new shortcut. To switch to Virtual Console. You can press Control Alt F3. Enter your user name, followed by your buzzword. Timbers enter. Now you can check the determinant which you are connected to using the TTY comment. You can press Alt Control F2 to return back to the graphical view. The exercise chilled section explanation. Hoping that terminal to check your hostname. You can check your current working directory using the PWD command to move to the slash users slash bin directory. And move back to your home directory. You can use CD, CD to your home directory or cd tilde to check to define an alias for the touch command. Here I defined an alias th for the touch command. To check the new alias and creating testfile. To check. To check the type of the PWD command. You can use the type comment. And to change the location of the echo command, you can use the which command to show the contents of the best variable. And to show all of the current variables defined a new shell environment. To list your home directory content. You can use Ls if you are currently on your home directory. If you aren't in your home directory, you can use ls, followed by the Beth to your home directory, or detailed assign to aid your documents directory to the wet environment variable and making it permanent. Now, coming to the documents directory, to your home directory, you can use the editor to open our S5. I to go to Insert mood. Move the cursor to the end of the line, followed by the bath to the Documents directory. Princes came to go to the command type colon and WQ to save and exit and press enter closed terminal and open it again. You can now check the contents of the batch variable using the echo command. To use the slice VDC slash issue file to display instructions on how to power of the machine to users. You will need to switch to the root user. Use the editor of your choice to urban destination, ETC. Slash issue file. Press the switch to insert mode. The instructions. This escaped switched to comment mood column WQ to save and exit and press enter. To see the instructions, you will need to switch to Virtual Console. Brings art control, F4. Press Alt Control F2, switch back to graphical view to show the current date, formatted day, month, year type. Risk control D Twitch to regular users. Switch the user's password. Type the current password. No type the new password. You type the new buzzword. Buzzword updated successfully to show the last four lines in destination, ETC. Slash password file. To show the number of lines in destination, ETC. Slash hosts file. To show the content of the sludge disease stage hosts file, you can use the cat command to redo comment number five in the history. To run it for 100 seconds using the SNP command. And to keep current running in the foreground using especially decomposition. Press control C, plug out of the oven child using a specific key combination, Risk Control D, till we meet in the next exercise. Thanks.