Linux System Commands and Installation

Linux Installation and Usage

• After completing this chapter, you will be able to:
  • Prepare for and install Fedora Linux using good practices
    • Outline the structure of the Linux interface
    • Enter basic shell commands and find command documentation
    • Properly shut down the Linux operating system

Installing Linux

• OSs require a minimum set of hardware components to function properly
  • This information can be found in the manual, a file on the OS DVD, or on the vendor's website
• Each component should be checked against the Hardware Compatibility List (HCL) on the vendor's website

Fedora 28 Minimum Hardware Requirements:

• CPU: 1GHz or faster Intel x64 CPU
• RAM: 1GB
• Free disk space: 10GB
• Additional drive: DVD drive for DVD-based installation
• Peripheral devices: Fedora-compliant peripherals

Installation Media

• The most common source for Linux packages and the installation program is DVD media
  • To install from DVD, place the Linux DVD in the DVD drive and turn on the computer
• Most Linux distributions offer downloadable DVD images (ISO images) on their websites
  • These images can be written to blank writable DVDs using disc burning software
• Many Linux websites also allow the download of bootable live media DVD images
  • A fully functional graphical of Linux OS is loaded into RAM
  • A live image tests the OS on your computer to ensure all hardware drivers are detected properly
• Linux can be installed by imaging the DVD or live media DVD image to a USB flash drive
• Virtualization software is used to run an OS within an existing OS concurrently
  • Examples include Microsoft Hyper-V, VMWare, and Oracle VM VirtualBox
• Virtual machine (VM): each OS that is run within virtualization software
• Virtual machine host (VM host): underlying OS running the virtualization software
• To install Linux as a VM:
  • Download the standard DVD or live media DVD ISO image to a directory on your VM host
  • Open virtualization software and select create a new virtual machine
  • Specify the location of the appropriate ISO image
  • Virtualization software will boot directly from the ISO image

Performing Installation

• General installation stages for Fedora 28 Linux entail: starting the installation
• Choosing an installation language in addition to localization and system options
• Configuring disk partitions and filesystems
• Configuring user accounts
• Boot from Fedora installation media
  • A prompt to start the installations should appear
  • Troubleshooting actions can also be performed to fix any potential issues
  • If the troubleshooting option is selected then there will be four additional options
  • Start Fedora-Workstation-Live 28 in basic graphics mode
  • Run a memory test
  • Boot from local drive
  • Return to main menu
• In most cases, the troubleshooting options are not necessary when installing Fedora Linux
  • Simply select Start Fedora-Workstation-Live 28 to start a live Fedora system
  • Upon loading, a welcome screen prompting to install Fedora Linux on permanent storage will show
  • Select Install to Hard Drive and the Fedora installation program starts

Choosing an Installation Language/Localization and System Options:

• You will be prompted to choose an installation language
• Keyboard model and layout are automatically detected
• The network interfaces are set to obtain network configurations automatically using the DHCP protocol
• Date and time are automatically obtained from the internet if the network has a connection
• An installation destination must be manually selected prior to the commencement of the installation
  • A permanent storage device that will contain the Linux OS must be selected
• Most common storage devices for storing Linux OS are hard disks such as:
  • Parallel Advanced Technology Attachment (PATA)
  • Serial Advanced Technology Attachment (SATA)
  • Non-Volatile Memory Express (NVMe)
  • Small Computer Systems Interface (SCSI)
  • Serial Attached SCSI (SAS)
• Selecting the Installation Destination icon presents a list of different permanent storage devices
  • If there are multiple devices you can pick which one to install Linux on
  • Linux can also be installed on an external iSCSI or FCoE Storage Area Network (SAN), Direct Access Storage Device (DASD), Multipath IO (MPIO), or firmware Redundant Array of Inexpensive Disks (RAID)

Configuring Disk Partitions and Filesystems

• Each hard disk is divided into partitions
  • Partitions are formatted with filesystems and filesystems specify structure on how data should reside on the hard disk
• Maximum four primary partitions
• Extended partition can be divided into logical drives
• Master boot record (MBR) is the table of all partition information for a certain hard disk or SSD
• Filesystems can be accessed by Linux if it is attached (mounted) to a certain directory
• The Fedora installation program can automatically create partitions
  • Manually partitioning is good practice
• Linux requires two partitions
  • A partition mounted to the root directory
  • A partition for virtual memory (swap memory): Area on hard disk used to store information normally residing in physical memory (RAM)
• Different file systems include Ext2, Ext3, Ext4, VFAT, and XFS
• Journaling keeps track of the information written to the hard drive
• Selecting an installation destination means that the installation program will prompt to choose an automatic or custom partitioning
• Instead of standard partitions, choose a partition scheme that creates logical volumes -Use the Logical Volume Manager (LVM)
  • Support the new B-tree Filesystem (BTRFS)
• Easier system recovery can be achieved when selecting a standard partition scheme

Configuring User Accounts

• Authentication requires:
  • Users to log in via valid user name and password
• Two user accounts should be configured:
  • Administrator account (root): full rights to system
• Regular user account: system administration tasks

Basic Linux Usage

• Consists of different types of user interfaces that are essential to understand
• Basic tasks include command Execution
• Obtaining online help
  • Shutting down the Linux system

Shells, Terminals & Kernel

• Terminal: channel allowing users to log on to the kernel locally or across a network
• Shell: user interface which accepts user inputs and transfers them to the kernel
• BASH Shell (Bourne Again Shell): default Linux shell
• Linux can have many terminals that allow logging in to the computer locally or across a network
• Graphical user interface
  • Start GUI environment on top of BASH shell
  • Switch to a graphical terminal
  • From the local server, use key combinations to change to separate terminal
  • Can use Ctrl+Alt+F2
• Command line prompt reflects the type of user; “#” reflects root and “$” reflects regular user
• Default GUI environment in Fedora Linux is GNOME
• The command-line terminal can be accessed through the Activities menu in the upper left of the desktop
  • Navigate to Show Applications, Utilities, Terminal

Basic Shell Commands

• Commands indicate the name of the program to be executed and are case sensitive
• Options are specific letters starting with a dash "-" that appear after command name
  • Options alter how a command works
• Arguments specify the command's specific working parameters
• Arguments do not start with a dash

Shell Metacharacters

• Keyboard characters with special meaning:
• A $ tells the shell that the following text refers to a variable
• Avoid the use of metacharacters unless using their special functionality
• Single quotation marks '' protect metacharacters from being interpreted specially by the shell

Getting command help

• Manual (man) pages: most common documentation for Linux commands
  • At the command prompt, type man command followed by command name
• Manual pages
  • Contain different sections
  • Section numbers describe the category of the command in the manual page database
  • Searchable by keyword
• GNU info Pages
  • Originally intended to replace the man command in Linux
    • At the command prompt, type info command followed by command name
  • Certain commands do not have manual or info pages
  • Those that are built into the BASH shell

Shutting Down Linux

• The OS handles writing data from computer memory to the disk drives
  • Simply turning off power to the computer is not recommended as it can cause user and system file damage
• Shutdown command
  • Can halt or reboot your computer after a certain period of time

Useful Shutdown Commands:

• shutdown –P +4: Powers off your system in four minutes
• shutdown –H +4: Halts the operating system in four minutes but does not invoke the ACPI function
• shutdown -r +4: Reboots your system in four minutes
• shutdown -P now: Powers off your system immediately
• shutdown -r now: Reboots your system immediately
• shutdown -c: Cancels a scheduled shutdown
• halt: Halts your system immediately, but does not power it off
• poweroff: Powers off your system immediately
• reboot: Reboots your system immediately

Summary

• Installation requires the verification of hardware requirements and compatibility
• Linux installation media are available as an ISO image from the Internet
• Typical Linux installation prompts for language, Date, Time zone, keyboard layout, network, user account and permanent storage configurations
• Users must log in to a terminal and receive a shell before they are able to interact with the Linux system and kernel
• Use command prompts to perform system tasks, obtain help manuals, and shut down the Linux system
  • The shell understands special shell metacharacters and arguments, and is case sensitive.