Introduction to Linux Fundamentals

Linux Installation and Usage

• Chapter focuses on preparing for, installing, and using Fedora Linux
• It provides an outline of the Linux interface structure
• Focuses on entering basic shell commands
• Teaches how to find command documentation, and properly shut down Linux

Installing Linux

• Installing any OS requires meeting minimum hardware requirements listed in the OS manual, DVD, or vendor website
• Hardware Compatibility List (HCL) on the vendor's website lists compatible devices

Fedora 28 Minimum Hardware Requirements

• CPU: 1GHz or faster Intel x64
• RAM: 1GB
• Free Disk Space: 10GB
• DVD drive for DVD-based installation
• Fedora-compliant peripheral devices

Installation Media

• DVD media are the most common source for the Linux packages and installation programs
• Linux can be installed from DVD by placing the DVD in the DVD drive and turning on the computer
• Most Linux distributions offer downloadable DVD images, also known as ISO images, on their websites
• ISO images can be written to a blank writable DVD using disc burning software

Bootable Live Media

• Many Linux websites provide live media DVD images
• Live media images allow a fully functional OS to load directly into RAM to test hardware driver compatibility
• Linux can be installed to a USB flash drive, if the computer lacks a DVD drive

Virtualization Software

• Virtualization software such as Microsoft Hyper-V, VMWare, and Oracle VM VirtualBox can run an OS within an existing OS concurrently
• Virtual Machine (VM) refers to each OS running within the software
• The underlying OS running the virtualization software is the "VM host"

Installing Linux as a VM

• The standard DVD or live media DVD ISO image are downloaded to a directory on the VM host
• Virtualization software is opened, and a new virtual machine is created
• The location of the appropriate ISO image is chosen within the setup
• Virtualization software will boot directly from the ISO image

Performing the Installation

• General stages for Fedora 28 Linux installation include:
• Starting the installation
• Choosing an installation language and system options
• Configuring disk partitions and filesystems
• Configuring user accounts

Starting Installation

• To begin, boot from Fedora installation media
• Options to either start the installation directly or perform troubleshooting are offered
• If troubleshooting is selected 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

Beginning the Installation

• Troubleshooting options are usually unnecessary
• Choose "Start Fedora-Workstation-Live 28" to start a live Fedora System
• A welcome screen will appear prompting the Linux installation on permanent storage
• Selecting, "Install to Hard Drive" will start the installation program

Installation Language and Localization

• Prompts to choose the installation language will appear
• The keyboard model and layout are automatically detected
• The network interface obtains network configuration automatically using DHCP protocol
• Date and time are automatically obtained from the Internet if a network connection is established

Installation Destination

• A permanent storage device for the OS must be manually selected
• Common storage devices for storing Linux operating systems are hard disks.
• 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 a Destination

• Choosing the Installation Destination icon brings you to a list of permanent storage devices
• If there are multiple disk devices, select the disk to install Linux onto
• Linux can 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)

Disk Partitions and Filesystems

• Each hard disk is divided into partitions, formatted with filesystems, defining how data should reside
• Can have at most four primary partitions
• An extended partition can be divided into logical drives
• Master Boot Record (MBR) provides partition information for a hard disk or SSD

Filesystem Access

• File systems can be accessed if it is attached to a certain directory
• Fedora installation program can automatically create partitions
• Manual partitioning is generally good practice

Linux Partitions

• Linux generally requires two partitions
• Partition mounted to the root directory
• Partition for virtual memory (swap memory) stores data from the physical memory (RAM)

Partitioning Schemes

• Different filesystem types are: Ext2, Ext3, Ext4, VFAT, and XFS
• Journaling keeps track of the information written to the hard drive
• Once the installation destination is selected, the installation program will prompt to choose automatic or custom partitioning

Partitioning Options

• Instead of standard partitions, a partition scheme that creates logical volumes can be chosen
• The Logical Volume Manager (LVM) can be used
• This helps support the B-tree Filesystem (BTRFS)
• Easier system recovery
• A standard partition scheme can be chosen
• It is important the contents of disk partitions are not encrypted

User Accounts

• Authentication is required through valid username and password
• Two user accounts should be configured
• Administrator account with root privileges for full rights to the system
• Regular user account with limited system administration tasks

Basic Linux Usage

• It's essential to learn different types of user interfaces
• Basic tasks:
  • Command execution
  • Obtaining online help
  • Shutting down the Linux system

Shells and Terminals

• Terminal: channel allowing log on to the kernel locally or across network
• Shell: user interface accepting input and transferring it to the kernel
• BASH: default Linux shell
• Linux has many terminals for local and network log-ins

Linux Interface

• Graphical user interface starts environment on top of BASH shell
• Switch to graphical terminal from local server using key combinations to change to separate terminal
• Ctrl+Alt+F2
• Command line prompt changes to reflect the type of user logged-in

Command Line

• Root user has the "#" symbol at the end of the line
• Regular user has the "$" symbol at the end of the line
• GNOME is the default GUI environment in Fedora Linux
• The command-line terminal can be accessed in the Activities menu, located in the top left corner of the desktop

Working with Commands

• Commands: execute programs
• Case sensitive
• Options: specific letters starting with a dash "-"
• Alter the way command works
• Arguments: specific working parameters
• Do not start with dash

Shell Metacharacters

• Metacharacters: keyboard characters with special meaning
• A "$" alerts the shell about an upcoming variable
• Single Quotation marks '' protect metacharacters

Getting Command Help

• Manual (man) pages: documentation for Linux commands
• At command prompt, type "man" command followed by command name
• Manual pages contain multiple, searchable sections

Manual Page Section Numbers

• Section 1: Commands that any user can execute
• Section 2: Linux system calls
• Section 3: Library routines
• Section 4: Special device files
• Section 5: File formats
• Section 6: Games
• Section 7: Miscellaneous
• Section 8: Commands only root user can execture
• Section 9 Linux kernel routines
• Section n: New commands not organized

Additional Help

• GNU info pages: replacement for man command in Linux
• At command prompt, type "info" command followed by command name
• Some commands do not have manual or info pages, especially functions in BASH shell

Shutting Down Linux

• The OS must write data from memory to the disk drives before shutdown
• Turning off power could damage user and system files
• The shutdown command can halt or reboot the computer after a time has passed

Shutdown Commands

• shutdown –P +4 Powers off the system in four minutes
• shutdown –H +4 Halts, but does not invoke the ACPI function in BIOS to turn off power to the PC
• shutdown -r +4 Reboots PC in four minutes
• shutdown -P now Powers PC off immediately
• shutdown -r now Reboots the PC immediately
• shutdown -c Cancels a scheduled shut down Halt: Halts the PC immediately, but does not power off
• Poweroff: Powers off your system immediately
• Reboot: Reboots system immediately

Summary

• Hardware requirements and compatibility must be verified before installation
• Linux installation media is obtained by downloading an ISO image from the Internet
• Typical installation sequence: prompts for:
• Language
• Date
• Time zone
• Keyboard layout
• Network configuration
• User account configuration
• Storage configuration

Summary Continued

• Users must log in to a terminal and receive a shell before interacting with Linux and the kernel
• Regardless of terminal type, users can enter:
  • Commands
  • Options
  • Arguments
  • At a shell prompt to perform tasks
• Shell is case-sensitive
• Shell understands special characters, called "Shell Metacharacters" which should be protected if not used in their special meanings