Week 4 Learning Journal

I followed the LPI Linux Essentials Certification from acloud.guru and gained knowledge about these chapters.

CHAPTER 1 - Getting Started

CHAPTER 2 - Linux Evolution and Popular Operating Systems

CHAPTER 3 - Major Open-Source Applications

CHAPTER 4 - Open-Source Software and Licensing

CHAPTER 5 - ICT Skills and Working in Linux

CHAPTER 6 - Command Line Basics

CHAPTER 7 - Using the Command Line to Get Help

CHAPTER 8 - Using Directories and Listing Files

CHAPTER 9 - Creating, Moving, and Deleting Files

CHAPTER 10 - Archiving Files on the Command Line

CHAPTER 11 - Searching and Extracting Data from Files

CHAPTER 12 - Turning Commands into a Script

CHAPTER 13 - Choosing an Operating System

CHAPTER 14 - Understanding Computer Hardware

CHAPTER 15 - Where Data Is Stored

CHAPTER 16 - Your Computer on the Network

CHAPTER 17 - Basic Security and Identifying User Types

CHAPTER 18 - Creating Users and Groups

CHAPTER 19 - Managing File Permissions and Ownership

CHAPTER 20 - Special Directories and Files

CHAPTER 21 - Linux Essentials Practice Exam 010

CHAPTER 22 - Final Steps

Keywords Learned during the Completion of 22 Chapters

Command Line Tools

• htop: Interactive process viewer for system monitoring.
• pwd: Command to print the current working directory.
• cat /etc/issue: Command to display the system identification file.
• sudo dpkg -i (package_name): Command to install a .deb package.
• sudo dpkg --remove (package_name): Command to remove a .deb package.

Documentation Pages

• Man pages basics and how to use - flags with it.
• Info pages are much more detailed.

Files and Directories

Common Directories

• /bin: Contains commands runnable by all users.
• /boot: Contains important files for booting the system.
• /dev: Contains device files like block devices.
• /etc: Contains configuration files.
• /home: Contains user home directories.
• /lib: Contains shared libraries.
• /mnt: Temporarily mounted filesystems.
• /opt: Contains optional packages.
• /proc: Contains kernel process and files.
• /root: Home directory for the root user.
• /run: Contains application state files.
• /sbin: Contains system administration binaries.
• /srv: Contains service data.
• /tmp: Contains temporary data, non-persistent.
• /usr: Contains user binaries.
• /var: Contains variable data files.

File Navigation

• pwd: Command to print the current working directory.
• cd: Command to change directories.
  • Press tab to complete commands.
  • .: Represents the current directory.
  • ..: Represents the parent directory.
  • ../..: Moves two levels up.
  • -: Returns to the previous directory.
• ls -a: Command to list all files, including hidden ones.
• Hidden files are not secret files; permissions are used instead.
• ls -A vs ls -a: Difference in listing hidden files.

Environment

• env: Command to display environment variables.

File Operations

Basic Commands

• mkdir: Command to create directories.
• cp -r <source> <destination>: Command to copy recursively.
• mv <source> <destination>: Command to move or rename files/directories.
• rm -r <destination>: Command to remove directories.

File Creation

• touch <name>: Command to create an empty file.
• cp <source> <destination>: Command to copy files.
• mv <source> <destination>: Command to move or rename files.
• rm <file>: Command to remove files.
• file: Command to determine file type.

Other Operations

• Moving a file over another (mv file2 file1) will erase file1.

File Attributes

• -p tag for creating a directory and subdirectories.
• -s: Symbolic link.
• -v: Command to get detailed information.

Miscellaneous

• Linux is case-sensitive.
• Globbing:
  • ?: Matches any single character.
  • *: Matches zero or more characters.
  • []: Matches any one of the enclosed characters.
  • ^, $, {}, |: Special characters for pattern matching.

Lab Performances

• Understood concepts of moving, copying, and removing files and folders using globbing.

Chapter 3.1: Archiving Files on Command Lines

• Learned about archiving using tar command with options like c, x, r, t, f, and deleting files in the archive without extracting it.
• Explored compression techniques using gzip, bzip2, and zip with options -z, -j, and zip.
• Lab tasks performed:
  • Created an archive using tar with various options.
  • Compressed archives using gzip and tar.
  • Extracted files from an archive using tar.

Chapter 3.2: Searching and Extracting Data from Files

• Studied usage of grep and | command along with their common applications.
• Learned about I/O redirection using >, >>, and <.
• Explored regular expressions (regex).
• Lab tasks performed:
  • Answered questions about file contents using grep and regular expressions.
  • Redirected output to a file named value.txt.

Additional Resources and Labs

• Conducted additional labs focusing on parsing data from large files using grep, piping, and regular expressions.
• Tasks included determining the number of files and folders, unpacked entries, and total entries in log files.
• Explored various regex patterns to extract specific data from files.
• Output of tasks directed to ~/value.txt.

Learning Objectives

• Completed 3 out of 3 learning objectives for Chapter 3.
• Completed 4 out of 4 learning objectives for Additional Resources and Labs.

Turning Commands into a Script

3.3 Turning Commands into a Script

• Explored the autonomy of shell scripts.
• Created a basic shell script using #!/bin/bash and commented lines.
• Made the script executable using chmod +x.
• Learned basics of text editors like vim and nano, and utilized vimtutor.

About This Lab

In this hands-on lab, wrote a shell script for connecting to Linux Academy Linux servers from another Linux (or Mac) host, without having to first accept the RSA fingerprint.

Learning Objectives

• Determined options to be used with the ssh command.
• Built a script from the required commands.
• Executed and verified the script.
• Added the new bin directory to the PATH variable.

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Choosing an Operating System

4.1 Choosing an Operating System

• Explored different operating systems and their uses, including distribution lifecycles.

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Understanding Computer Hardware

4.2 Understanding Computer Hardware

• Utilized commands like cat /cpu/proc, free, df -h, ifconfig to gather hardware information.

About This Lab

Practiced locating hardware information to ensure appropriate usage and facilitate the installation of additional drivers.

Learning Objectives

• Determined available storage using df -h.
• Determined the number of CPUs/cores using cat /proc/cpuinfo.
• Determined CPU speed using cat /proc/cpuinfo.
• Determined installed RAM using sudo dmidecode and sudo cat /proc/meminfo.
• Determined swap usage using free -m.
• Determined the BIOS version using sudo lshw and sudo dmidecode.

Where Data Is Stored

4.3 Where Data Is Stored

Configuration Files in /etc

• Explored the purpose of /etc directory and its subfolders.
• Learned about configuration files like fstab and others.

Processes

• Utilized commands like ps to view running processes.
  • ps aux
  • top

System Messaging

• Explored system messaging using dmesg.

About This Lab

In this hands-on lab, practiced finding and viewing processes running on a Linux system, which is fundamental for systems administration.

Learning Objectives

• Determined the number of processes currently running.
• Determined the current system load.
• Determined how many processes are running as cloud_user.
• Determined the PID of the xfce4-session process.
• Determined how many threads the xfce4-session process is using.
• Wrote a small shell script to return the number of threads in a process.

System Logs Lab

• Practiced working with system logs, a common task for Linux service administrators.

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Your Computer on the Network

4.4 Your Computer on the Network

Internet, Network, and Routers

• Explored querying DNS client configuration.
• Explored querying network configurations.

About This Lab

In this hands-on lab, determined the network configuration for the eth0 interface of the lab host.

Learning Objectives

• Determined the IP address using sudo ip addr show.
• Determined the MAC address using sudo ip addr show.
• Determined the gateway using sudo ip route show.
• Determined the DNS server using cat /etc/resolv.conf | grep nameserver.

DNS Configuration Lab

• Verified network DNS configuration settings and performed several DNS queries.

Learning Objectives

• Determined the configured DNS host using cat /etc/resolv.conf.
• Performed a DNS lookup on www.acloudguru.com using the configured DNS host.
• Performed a DNS lookup of www.acloudguru.com using another DNS host.
• Tested connectivity to www.acloudguru.com using ping.

Basic Security and Identifying User Types

5.1 Basic Security and Identifying User Types

User Types

• Differentiated between root and standard users.
• Explored system users.

About This Lab

In this hands-on lab, practiced working with users and groups in Linux, which is fundamental to managing Linux systems.

Learning Objectives

• Determined what groups sysuser belongs to using:
  • id sysuser
  • groups sysuser
  • cat /etc/group | grep sysuser
• Determined sysuser’s home directory using:
  • getent passwd sysuser
  • cat /etc/passwd | grep sysuser
• Determined sysuser’s login shell using:
  • getent passwd sysuser
  • cat /etc/passwd | grep sysuser

Creating Users and Groups

5.2 Creating Users and Groups

User and Group Commands

• Utilized user and group commands to manage users and groups.
• Learned about user IDs.

Boilerplate

• Discussed the purpose of the /etc/skel directory.

About This Lab

In this hands-on lab, practiced adding users and groups from the command line, a fundamental skill in Linux system administration.

Learning Objectives

• Created required users and groups using appropriate commands.
• Added members to the appropriate groups.
• Verified group membership configuration for all users.

Managing User and Group IDs

UID Scheme

• Determined the UID scheme by examining /etc/passwd.
• Determined the UID ranges for system users and standard users.
• Identified the absolute highest UID value for the current users.
• Chose a higher value for where UIDs on a remote host should begin.

GID Scheme

• Determined the GID scheme by examining /etc/group.
• Determined the highest GID value.
• Chose a higher value for where GIDs on a remote host should begin.

Managing File Permissions and Ownership

5.3 Managing File Permissions and Ownership

Understanding Permissions

• Differentiated between user, group, and everyone permissions.
• Explored the usage of chown and chmod commands.

About This Lab

In this hands-on lab, practiced managing Linux file and directory ownership and permissions, which is fundamental to Linux systems administration.

Learning Objectives

• Locked Bill’s, Susan’s, and Juan’s accounts.
• Created accounts for Nancy, Greg, and Jeremy.
• Removed Bill, Susan, and Juan as users and transferred ownership of their home directories.
• Changed permissions of directories to grant read and execute permissions to the group.

Special Directories and Files

5.4 Special Directories and Files

Using Temporary Files and Directories

• Retrieved and unpacked an archive.
• Created a temporary file from a directory listing.
• Moved files to a more persistent temporary directory.

Symbolic Links

• Created symbolic links for rpm_verify, rpm_dump, and rpm_load.
• Added ~/bin directory to the $PATH environment variable.
• Tested the symbolic links to verify functionality.

Summary of My Journey through Chapters 1 to 20

In my journey through Chapters 1 to 20, I delved deep into the world of Linux systems administration, covering a wide range of topics essential for managing and maintaining Linux-based systems. Here’s a comprehensive summary of what I learned:

Chapters 1 to 5: Introduction to Linux Basics

I started with the basics, understanding the Linux filesystem hierarchy, navigating directories, and manipulating files. I learned about basic commands like ls, cd, pwd, and cat, and explored concepts such as permissions, ownership, and file manipulation.

Chapters 6 to 10: Working with Processes, Services, and Package Management

Moving forward, I gained insights into managing processes, services, and software packages. I explored commands like ps, top, systemctl, and apt-get, understanding how to start, stop, and manage services efficiently. Additionally, I learned about package management tools and techniques for installing, updating, and removing software packages.

Chapters 11 to 15: Networking and System Logs

My journey continued with networking fundamentals, including DNS resolution, IP addressing, and network configuration. I explored commands like ifconfig, ip, and nslookup, gaining the skills to troubleshoot network connectivity issues effectively. Furthermore, I learned how to analyze system logs, interpret log entries, and extract relevant information for troubleshooting purposes.

Chapters 16 to 20: Security, Users, Permissions, and Special Files

In the final stretch, I focused on security-related aspects, user management, and file permissions. I learned about user types, group management, and configuring permissions using commands like chown and chmod. Additionally, I explored concepts such as special directories, symbolic links, and temporary files, enhancing my understanding of file system organization and management.

Conclusion

Through diligent study and hands-on practice, I have acquired a solid foundation in Linux systems administration. From basic filesystem operations to advanced networking and security concepts, I have developed the skills and knowledge necessary to manage Linux-based systems effectively. As I continue my journey, I will remember to apply these principles in real-world scenarios, continuously refine my skills, and stay updated with the latest developments in the Linux ecosystem. With determination and persistence, I am well-equipped to tackle the challenges of Linux systems administration with confidence.