CompTIA Linux+ (LX0-103 and LX0-104) (Part 1 of 2)

Debian is a customizable, powerful Linux distribution developed by a large open-source community. Backtrack and Helix show purpose-built tools for security testing and forensics, guiding your choice by goals.

Compare closed source and open source licensing, learn GPL and LGPL implications, and see how permissive licenses like MIT and Apache govern use, modification, and distribution.

Explore pre-installation tasks for Linux, review licensing issues, and outline what we must do before starting the installation.

Gather hardware details and drivers during pre-installation to ensure Linux compatibility on servers, including interrupt settings and IP addresses; choose installation destination and partitioning with dual-boot or CD options.

Download installation files from online linux distros, such as those found via Distrowatch, then burn the ISO to a DVD or CD and install from the media drive.

Explore installation types such as CDs, DVDs, ISO files, and USB boot media, including live CD/DVD with RAM drive, and net installation that downloads the rest via network or NFS.

Explore partitioning as a key pre-install step by using non-destructive tools like parted or gparted to create or resize partitions during installation, including resizing Windows partitions.

Join a practical linux installation in a vmware virtual machine for the CompTIA Linux+ course, using a fedora 12 iso to set memory and disk, then explore grub and commands.

The lecture demonstrates logging into Debian with the trainer account, then explores the desktop, multiple workspaces, and open source apps like image manipulation program and OpenOffice Draw, Writer, Impress.

Introduce the graphical user interface, the most comfortable and familiar part of any operating system. Explore how the graphical user interface shapes user interaction and navigation.

Explore the evolution of X Windows and the graphical user interface, illustrating how GUI architecture provides kernel-to-graphics interaction and modular components that can vary across Linux systems.

Demonstrates two Linux desktop environments, GNOME and KDE, highlighting the task bar and start-like menus, plus basic terminal commands such as who am i and pwd.

Explore the KDE desktop environment, a Windows-like graphical interface with the K button and K bar start menu, and its support for up to four customizable desktops.

Explore how Linux integrates with shells and GUIs, interact with hardware, manage file systems, and run applications like OpenOffice and Firefox, while server tools handle user management, network and monitoring.

Master keyboard-focused shell navigation with keystroke tricks to move through recent output. Use shift-page up, shift-page down, and control-t to jump to the top or bottom without leaving the keyboard.

Explore shell metacharacters and command composition, including grouping with braces and colons, and learn how background execution and pipes control flow in commands like cd /bin && ls.

Learn to use named pipes, created with mkfifo, to share data between applications as a persistent, file-backed conduit operating as a first-in, first-out channel.

Demonstrate named pipes (fifos) to transfer data between shells by creating a fifo, redirecting command output into it, reading from it with cat, then removing the pipe.

Learn how to read a man page, which is organized by name, synopsis, and description, and navigate it in the shell using the space bar and q to quit.

Compare man pages and info pages, and learn how end users access help in the shell for commands you can type; note that not all commands have a manual page.

Explore linux help commands and the manual, showing piping to more for paged output, searching within manual pages, and quitting with q while inspecting sections like locale.

Explore help options with man -k and apropos, view command details via ls --help, and read outputs with more; navigate using up arrow, spacebar, and q to quit.

Explore how the GUI is composed, how it works, and how it interacts with Windows in the kernel, plus common applications and the command line interface.

Master the cd command to navigate directories using absolute paths and relative paths, move up with dot dot, use dot for the current directory, and understand permissions and root access.

Learn to use pushd and popd to create memory-stored directory references, quickly move between frequently used directories, with tips to use history and the up arrow to recall cd commands.

Delves into vi commands for text editing, including append and insert with colon, delete with de or D, yank and paste, undo, quit, and hjkl navigation.

Demonstrate creating hard and symbolic links in Linux using the ln command and GUI tools; verify links with cat and ls, and show how moving a linked file affects accessibility.

Discover how Linux treats every item as a file and learn commands to reveal file information, including ls -l, file, stat, and test, with discussion on naming conventions.

Explore file metadata by using the RLS command with the Lf option to display long information, including permissions, links, owner and group, size, date, and file type.

Explore removable storage and the rise of terabyte-scale drives. Learn how mounting these devices merges them into your system.

Mount volumes like optical and USB drives into a single root directory with the mount command, using type, device file, and mount point options; desktop systems often mount cds automatically.

Learn to perform privilege escalation by switching from a regular user to root with su, or by using sudo to run commands like mount and unmount as root.

Explore Linux file systems, directories, and mounting drives, and practice creating, editing, copying, and deleting files manually using absolute and relative paths, including cd commands, in the shell.

Explore system administration by managing the operating system, handling authentication and authorization, configuring discretionary permissions for files and directories for users and groups, and setting environment variables and gooey environment.

Delve into authentication, users and groups. Explore the basics of authorization and triple A concepts, with accounting and logging addressed later.

Explain how the shadow file tracks usernames and passwords, recording last change date, min and max days, warning/grace periods, and automatic disable to prevent brute-force password attacks.

Add the trainer to the sudoers file to enable password-protected sudo from any computer, editing with vi and verifying the change by testing sudo.

Create a new Linux user with the useradd command, including add user variants, interactive prompts, and switches for home directory, group id, encrypted password, shell, user id, and skeleton directory.

Explore the /etc/default/useradd file, which sets default values for the user account, including primary group, home directory, shell, skeleton directory, grace period, and expiration dates.

The /etc/skel directory stores the skeleton startup files copied into every new user's home directory at login, including hidden dot files like .bashrc, .bash_logout, and .profile.

Configure the /etc/adduser.conf file to establish defaults for adduser, including default shell, home directory, uid and gid ranges, quotas, and extra groups, with optional overrides.

Create and manage user accounts from the command line, inspecting login definitions, aging controls, and password and shadow files, using useradd and adduser to set home directories and IDs.

Explore GUI admin tools for adding a new user account, ensure it includes group assignments and consistent, correct configuration, and learn when a command-line script is faster for bulk migrations.

Learn how to create new user accounts using the graphical user interface, including setting a password, optionally specifying a user ID or group, and adjusting account properties.

Explore safe methods to modify user accounts using the usermod command, updating home directories, primary groups, logins, usernames, and shells while avoiding direct edits to password or shadow files.

Demonstrate modifying linux user accounts with usermod to rename logins, move home directories (-d, -m), and set full names (-f), and contrast command-line options with gui tools in system administration.

Create groups to grant mass permissions to multiple users, using a group id and optional password or system group. Apply file permissions to a group instead of individuals.

Decide whether to lock or delete a user account, and avoid reusing user IDs to prevent permission creeping; delete groups when needed.

Delete users and groups with userdel and groupdel, after locking accounts and verifying changes in /etc/shadow and /etc/passwd. Confirm removals and handle non-existent users, noting Linux is case sensitive.

Explore how Linux file ownership differs from Windows ACL entries, showing how the owner and primary group determine permissions and how the owner can set or change them.

Change your primary group with the newgrp command to access a file owned by another group, then use chown and chgrp to modify its owner and group.

Use the umask to subtract a three-bit mask from default permissions when creating files or directories. Watch how 666 becomes 644 and the mask adjusts the 777 permissions.

Apply special permissions with chmod using numeric and symbolic forms; interpret leading zero and how the first digit controls user id, group id, and the sticky bit.

Learn to use and change environmental variables in the shell, and understand user environment configurations and the role of created variables, including named pipes as storage.

Explore the difference between shell and environmental variables, their lifetimes and scope, and examine common vars like path, home, mail, and prompt using the set command.

Set a variable by naming it, assigning a value with equals, for your custom scripts. View it with echo $var and export to make it permanent, at creation or later.

Learn how the path sets the search order for executables, with directories like /home, local/bin, and user bin, and how to append to the path or use full paths.

Change the shell prompt by editing the PS1 value to a custom string, using placeholders U for username, H for host name, and W for the current directory.

Learn how a prompt conveys username, hostname, and current directory to help you navigate, especially when you are remotely connected, and how you can customize it for usefulness and clarity.

Learn to view and create linux command aliases, test for conflicts with which, and map shortcuts like k list to a preferred command with color auto to customize the environment.

Save a command alias in an environment file to persist across sessions by editing dot profile and dot bashrc, then add an lz alias with color auto using vi.

Learn how Linux installers configure the GUI automatically and when to start the GUI manually with start X, plus manual X11 or X386 configurations in /etc.

Explore how to use GNOME's GUI to adjust screen resolution, refresh rate, and rotation. Choose between system-wide or user-specific defaults.

Explore appearance preferences in Linux, including themes, backgrounds, and font options, mirroring a Windows environment. Change background colors and downloadable themes to improve focus with solid, light colors.

Configure mouse preferences to tailor input, including ambidextrous use, left- or right-handed setups, and pointer speed, while understanding click behaviors and efficient movement with a mouse pad.

Configure the mouse and keyboard settings, including handedness, pointer visibility, and double-click speed. Explore keyboard layouts and regional options, such as the United States standard and Dvorak.

Start the X Windows GUI using start X on older Linux systems. Turn off the desktop management with stop or stop X from the init.d/gdm directory, using root or sudo.

Explore authentication, authorization, and accounting basics; manage users and groups, apply file permissions, tune environmental variables, and optimize the GUI to secure and efficiently operate a Linux system.

Explore packages and package managers for application management, then learn to build installations from source code, highlighting ease, flexibility, and options for windows users familiar with easy installers.

Explore how binaries target specific hardware and operating systems, and how source code, as uncompiled text, is compiled and linked to run on a chosen platform.

Explore various package managers and types of packages, including rpm, apt, yum, and yast, and learn to use their command line options and help or man pages to install software.

Watch how to install a package using the synaptic package manager GUI: browse categories such as games, search for items, mark affected components, and apply changes to complete installation.

View installed software on your Linux system using the gooey or command-line package managers, and see what is installed with apt show or rpm -q.

Use the command line to remove packages with apt get remove and auto remove, review with synaptic, mark for removal, apply, and be careful not to delete components like asteroids.

Define and manage repositories as storage locations for packages, local or networked, public or private, with access for installation programs; choose repositories via GUI or command line.

Use Synaptic's software sources to manage repositories and choose where to download software. Include options like officially supported, source code, third-party software, updates, and necessary authentication to log in.

Explore source code software, enabling downloads as text files instead of bulky install packages, and learn how missing libraries during compilation can stress users in the Linux environment.

Download the source code from a tarball, extract it, then compile and link to build a binary using libraries that handle input and output for your operating system and hardware.

Learn to extract tar archives from downloaded tar balls by using tar with -z, -x, -v, and -f, decompressing gz or tgz files and extracting to a chosen directory.

Download a source code tarball from SourceForge, extract it with tar, install the lib SDL development package, configure, compile with make, and install the program on Linux.

Learn system configurations for Linux hardware, formatting drives, creating partitions and volumes, mounting and auto-mount, plus quotas, swap, RAID-based recovery, and recognizing USB, CD-ROM, and PCI devices.

Explore disk management basics, review hard drive components and terminology, and learn tools for partitioning and formatting drives.

Explain how ATA/IDE disk drives use master/slave configurations and drive numbering, then describe SCSI bus mastering and daisy-chaining that improves throughput and supports many devices.

Explore drive components like platters, a center spindle, and a read/write head on an arm that moves to tracks and sectors, and note how rpm affects seek time and performance.

Explore drive components, compare hard disk drives with solid state drives, and learn how to designate storage by volumes and partitions for Linux systems.

Understand that partitioning a single drive does not increase capacity or speed; use root and swap partitions to organize files and virtual memory, and consider separate drives for true performance.

Use fdisk to create and format partitions, describe drive geometry, and specify partition size and name, logically partitioning the drive into distinct partitions.

Explore parted, a text mode partition editor, to create partitions and file systems from the command line by specifying the /dev device, file system type, and start/stop addresses.

Learn to use fdisk to list partitions, create a primary partition, and write changes to a virtual disk, and verify the partition table.

Configure automatic detection of new drives using /etc/fstab, enabling predefined templates to mount drives on reboot and automate drive setup.

Demonstrate mounting an iso as a loop device in Debian, creating a loop test directory, mounting and navigating the loop file system, and unmounting to use virtual disks.

Set quotas to limit disk space per user or group based on file ownership, choosing hard or soft limits, and manage them via FS tab file in the Etsy folder.

Enable quotas by adding entries to the fstab file to set space limits for users or groups. Learn how to configure quota entries in fstab to manage disk usage.

Learn to use the edquota tool to rewrite the fstab file, leveraging a vi-like interface and mastering edit mode and command mode for effective quota management.

Edit the soft quota time limit (default seven days) and then use the rep quota tool to confirm that quotas are running and functioning as expected.

Swap space uses a hard drive as virtual memory to extend RAM, but it's slower than real memory. Decide swap size near RAM and set a priority within swap partitions.

Log in as root to create new swap space, choosing a partition or a swap file, designate it with mk swap, then enable it with swap on.

Allocate swap space as a partition or a file; if using a file, fill it to size to avoid fragmentation, then use dd for input-to-output sector-by-sector copies in forensic work.

Manage swap using both command line and GUI tools, create new swap locations, and inspect usage to ensure you don't miss options when configuring swap space.

Learn how disk arrays use redundancy to expand storage beyond a single drive and maintain data access during failures, delivering fault tolerance and high uptime through raid types.

Explain raid level 3, a striping with parity approach that stores data across multiple drives and uses a parity drive to recreate missing data, less common than raid level five.

Explain how raid level 5 distributes parity across all disks, enabling rebuild after a single drive failure and ongoing access during replacement, with a minimum of three disks.

Demystify device management by exploring its meaning and purpose, and clarify the Linux /dev directory in this precursory overview.

Learn how Linux lists USB hubs and devices with lsusb, dump the USB hierarchy using -t, and inspect /proc/bus/usb/devices for detailed device information.

Learn to view PCI devices with the ls PCI command and its verbose mode, and inspect bus PCI location to see what’s found, defined, and hooked up to your system.

Examine Linux processes and module management, identifying what processes are, how to view them, kill or adjust priorities, and how to view kernel information and manage modules.

Learn how preemptive multitasking lets the operating system divide processor time between processes, contrasting it with cooperative multitasking and the playful origin of daemons.

Describe how Linux assigns process IDs, including kernel pid zero and the init daemon with pid one, and use init.d to restart, stop, or manage services for soft reboots.

Explore common ps command forms to view process priority, state, CPU time, memory, and user IDs across terminals and daemons on Linux.

ps aux outputs per‑process cpu and memory usage to identify misbehaving processes slowing the system; analyze start time, user, and related processes to decide on termination or priority adjustments.

Use the top command to display the top offenders and sort processes by CPU usage, time, or memory to view what matters most.

Demonstrates viewing processes and devices with ps and top, using options for full details and paging, and exploring the CIS directory (proc) to inspect buses and USB devices.

Learn how to manage rogue or misbehaving processes with the kill command. Use signals like SIGTERM (15), SIGHUP, SIGINT, SIGQUIT, and SIGKILL to interrupt, quit, or forcefully stop a process.

Learn to prioritize processes and manage their execution, focusing on foreground versus background operation to optimize how tasks run on the system.

Explore process forking by starting a shell and forking a sub shell to run a command, then returning to the main shell. Wait for the sub shell to finish.

Run commands in the background using an ampersand, letting you continue in the parent shell while the foreground process forks and executes in a sub shell.

View existing process priorities using the PRI column and the top command to assess ripple effects before adjusting a process's priority, and understand the suggested change range.

Use renice to change a running process's priority by its process ID, then restore the task to its original priority after the work completes.

This demo shows how to manage process priorities using the sleep command, nice, and renice, and how to inspect changes with ps -l and psl.

Explore kernel tuning and hardening to improve performance and security, using sysctl to adjust settings and the CIS control config file in the /etc directory.

Explore Linux sysctl network settings, including default forwarding and gateway behavior, icmp handling (echo ignore, redirects), ignore broadcasts, and source routing to manage routes and security.

Explore how Linux handles processes and kernel modules, learning to view, kill, and reprioritize processes, and to fine-tune and harden the kernel for performance and control.

Prepare for disasters with backups and restoration plans; automate routine maintenance so systems run themselves. Monitor Linux performance, establish baselines, and log events to prevent issues.

Develop a backup and restore plan that meets business needs to minimize downtime during backups and disaster recovery.

Explore the concept of data compression as a mathematical transformation that replaces common data patterns with smaller representations, covering symmetric vs asymmetric and lossless vs lossy algorithms.

Assess the compression ratio to quantify storage savings from a compression algorithm and file type, noting that some files compress poorly.

Explore lossless and lossy compression algorithms, from Huffman coding and run-length encoding to DCT and wavelets, and note that choosing an algorithm often requires research or sticking with Linux defaults.

Explore linux compression utilities, including compress, gzip as the replacement for compress, and formats like gz, zip, and bz2, with gunzip for unzipping.

Explore how gzip, as a replacement for compress, uses options like -d to decompress, -t to test, -v for verbose, -f to force, and compression level flags; learn gunzip.

Compare bzip2 and zip for compression; bzip2 offers higher ratios but is less popular and may be unavailable on some Linux versions.

Use the gui by right-clicking a file, selecting the zip option, and choosing the compression algorithm, avoiding the command line when possible.

Cpio collects and copies files to standard output for backups, while find locates backup targets with cpio using criteria like permissions, name, or last access times, and dump and restore.

Learn to back up with cpio by finding the trainer folder, piping files into cpio to create backup.cpio, then redirecting to /var/temp and compressing with gzip to backup.gz.

Explore dd, a sector-by-sector copy utility used for backups and forensic analysis on hard drives, noting it copies data without performing analysis.

Learn dd for backing up your file system and disks, including backing up the MBR and using input and output files to back up and restore data.

This lecture shows backing up a drive with dd by copying from SDA1 device to a file in home directory using block size 512 and count 1 under root permissions.

Explore the two primary scheduling commands in Unix/Linux: at for one-time tasks and cron for recurring jobs, and learn how to verify execution with job reports.

Learn to schedule a command at now plus one minute, redirect output to testing.txt, verify with date and cat, and observe that the job runs once.

Schedule tasks with the cron command to run on a repeated daily, weekly, or monthly basis by configuring what and when, using crontab and cron.d.

Read the crontab file to interpret frequency: minutes, hour, day of month, month, day of week, and the command to run. See how to review or remove unnecessary scheduled jobs.

Install the sysstat package to access mpstat, iostat, and SAR for processor, disk, and system activity monitoring. Use free, top, uptime, and vmstat to view current memory and swap.

Install the systat package using the synaptic package manager, search for systat, apply changes, and verify with mpstat and iostat commands.

Use iostat to monitor drive input and output and identify bottlenecks, noting that memory swapping can cause high io and slow system performance.

Install systat to run mpstat for cpu usage, i/o wait, and idle time, then use iostat -C and -d to monitor cpu and disk performance and spot bottlenecks.

Examine sar output to analyze cpu utilization, including user, system, io wait, and idle percentages, with repeated runs showing a brief history of each sample.

Explore how the SAR system activity reporter collects CPU and I/O statistics, demonstrates options like -A and -B, and shows defaults and cron scheduling for troubleshooting performance.

Explore how the uptime command reports system runtime since last boot, logged-in users, and load, while highlighting the importance of patches, updates, and occasional rebooting for security.

Explore memory statistics utilities and process monitoring using uptime, free, vmstat, and top, then use system monitor to view, end, and adjust processes and daemon files.

Learn how load average from the uptime command measures real-time CPU load over 1, 5, and 10 minutes to indicate overload and guide enterprise planning with Apache and MySQL.

Open a terminal, run the top command, and view the load average over the 110 and 15 minute periods to assess whether the cpu is overloaded.

Explore Linux log files such as boot, cron, mail, messages, secure, and X window logs to monitor startup, scheduled tasks, backups, and security events.

explore how to view logs in /var/log using less and sudo, inspect the message file for hardware detection, and interpret startup timing and device settings.

Explore editing the syslog config to specify facilities and severity levels, targeting log files such as mail, users, and daemons, and define where to store them.

Explore the eight syslog priorities from emergency to debug, including alert for subsystem failures, notice for configuration changes, and info for events, with debug for real-time troubleshooting.

Discover how syslog.conf determines what gets logged on a system, viewing and editing with less and sudo access. Inspect daemon log and facilities by severity levels, and search for errors.

Explore log rotation and its daemon, which keeps log files from getting too large by archiving and rotating them. Configure rotation in the log rotate config and inspect archived files.

Explore a sample logrotate.conf demonstrating how to set rotation frequency, create new log files, apply compression, and store rotation state in /etc/logrotate.d, with separate rules for temp files.

Explore how log rotation archives logs to keep files small, inspect /var/log with less, and review a logrotate setup that rotates weekly, preserves archives, creates empty logs, and avoids compression.

Learn how grep uses regular expressions to search text and log files, with options for case sensitivity, whole word versus partial matches, and inverse matching.

Understand head and tail: display the first or last lines of a file by default, with options to set line counts; tail highlights the most recent log entries.

Explore sed, a powerful stream editor for search and replace, deleting lines, and directing output to screen or files for reading log information.

Learn the network basics to build a foundation for understanding what happens behind the scenes when a Linux machine communicates with the internet or other servers beyond its local host.

Explore how network protocols and open standards like IP, TCP, and UDP via the OSI architecture enable cross-platform communication between Windows and Linux.

Explore the OSI reference model, the Open System Interconnect framework describing node-to-node communications across seven layers, with focus on the lower layers.

Describe the osi model's top layers: layer seven is the application layer and layer six is the presentation layer, with examples like word processing documents and mp3 files.

Identify how the data link layer uses the MAC address burned into your network interface card to deliver frames through switches. Observe that IP addresses are logical and may change.

Explore the OSI reference model's layered architecture, from application and session to transport, network, data link, and physical layers, and how these layers manage packaging, addressing, and transmission.

Explain how OSI upper layers map to TCP/IP application and transport, discuss ports and sessions, and describe IPv4/IPv6 addresses and Ethernet MAC addresses.

Learn IPv4, a 32-bit address in dotted decimal notation with four octets. Grasp classful origins, subnetting, and temporary fixes such as CIDR, NATting, and padding.

Explore the transition to IPv6, its 128-bit address space, hex notation with colons, and deployment across providers, focusing on configuring Linux systems for new address assignments.

Compare character based names and static host files with dynamic DNS mappings, and learn how DNS registers name to IP changes as network topology evolves.

Learn how source and destination ports in tcp/ip identify services and manage traffic, using well-known ports (80, 443, 53) and source ports (0 to 65,535) to keep sessions separate.

Inspect /etc/services with less to view ports, noting tcp/udp usage and common services, most ports are 1–1024, with some outside, and use search engine work to learn meanings.

Explore the triple a of authentication, authorization, and accounting, and learn how remote access relies on authentication, permission control, and logging of actions under accounting.

Learn to verify a user’s identity through authentication factors: something you know, something you have, and something you are. Explore practical examples like usernames, passwords, smart cards, tokens, and biometrics.

One-factor authentication is easy to break through social engineering and password exposure; adopt multi-factor authentication using two or more factors: something you know, something you are, or something you have.

Three-factor authentication combines password, biometrics, and a smart card or token to secure access, but the weakest link, often people, can undermine even strong systems.

Explore network services that simplify connectivity, including DNS and DHCP, and learn how they streamline communications for local area networks and Internet access.

Install the dhcp server package and run the dhcp daemon to set up a dhcp server, ensuring the server uses a static ip while it dynamically assigns addresses to clients.

Explore network time services and the NTP protocol, which keeps servers and clients synchronized to an authoritative time source to prevent replay attacks and ensure small time differences.

Watch a demo of viewing daemon startup options. Learn how the inetd config on Debian controls services, and how /etc/rc*.d directories list startup services that boot Linux.

Discover how the domain name system maps names to IP addresses with a hierarchical, zone-based structure managed by authoritative servers, acting like a scalable phone book for billions of URLs.

Learn to use DNS tools such as nslookup, dig, and host to resolve names, query authoritative name servers, inspect NS records, and perform forward lookups with debian.org.

Configure Bind to run a DNS server for your local network, defining the named.conf, authoritative zone, and host-to-ip mappings along with aliases and service mappings.

Install bind9 to turn the system into a dns server, examine the default route table and route hints, and review local host zones and forward lookups via route servers.

Manage the bind dns service by starting, stopping, or restarting it to recover from issues, using the init daemon and init.d or rc.d paths.

Start the bind9 service from the init.d path with the default configuration to run as a caching DNS server, caching queries for about 30 minutes.

Examine how the host file resolves names to IPs, guided by the name service switch, using local files and the loopback address before DNS.