Day-6 | Linux & Shell Scripting | Complete Shell Scripting Playlist| #aws #azure | #devops

Linux Operating System and Basics of Shell Scripting

In this section, Abhishek introduces the topic of Linux operating systems and the basics of shell scripting. He emphasizes the importance of understanding operating systems as a bridge between software and hardware.

Understanding Operating Systems

• Abhishek explains that an operating system acts as a bridge between software and hardware, facilitating communication.

• Key components of a server include hardware such as CPU, RAM, and IO, with software applications running on top.

• Users run software applications on purchased hardware, necessitating an operating system to facilitate communication between the two.

• Operating systems like Linux or Windows are essential for enabling applications to interact with hardware effectively.

Role of Operating Systems

• The operating system mediates communication between applications, hardware, and users in a cyclical process.

• Operating systems play a crucial role in ensuring that applications can function by facilitating interactions with hardware.

Popularity of Linux Operating System

• Linux is widely used in production systems due to its prevalence in testing and deployment environments.

• Reasons for Linux's popularity include being free compared to proprietary systems like Windows.

Linux vs. Windows Operating Systems

The discussion compares Linux and Windows operating systems, highlighting the differences in terms of security, distribution options, speed, and cost-effectiveness.

Linux as an Operating System

• Linux is known for its security features, eliminating the need for antivirus software compared to Windows.

• Various distributions of Linux are available such as Ubuntu, CentOS, Debian, offering flexibility based on user preferences.

• Speed is crucial for production systems; Linux's fast performance makes it a preferred choice over slower operating systems.

• Linux is favored for being fast, secure, and free—a combination that appeals to users seeking efficiency and cost-effectiveness.

Understanding the Architecture of Linux Operating System

Exploring the architecture of the Linux operating system by breaking down its components from kernel to system libraries.

Components of the Linux Operating System

• The kernel serves as the core component responsible for communication between hardware and software.

• System libraries support various tasks within the operating system structure.

• Kernel's primary responsibilities include device management, memory management, process management, and handling system calls.

• Kernel plays a vital role in managing devices efficiently within an operating system environment.

Understanding Operating Systems and Shell Scripting

In this section, the speaker delves into the fundamentals of operating systems, compilers, user processes, system software, and the importance of understanding a breadth of concepts in DevOps.

Fundamentals of Operating Systems

• System libraries like graphical GNU are part of the operating system.

• Operating systems compile code for running applications like Java or Python.

• Understanding compilers, user processes, and system software is fundamental to any operating system.

Depth vs. Breadth in DevOps Knowledge

• Emphasizes the importance of grasping a wide range of DevOps concepts rather than delving deeply into each.

• Suggests focusing on breadth initially to tackle interviews before diving deep into specific tools like Ansible or Puppet.

Importance of Shell Scripting in Linux

This segment explores the significance of shell scripting as a means to interact with an operating system without a graphical user interface.

Role of Shell Scripting

• Shell scripting serves as a communication tool with the operating system.

• In server environments without GUI, shell commands are essential for operations.

Commonality Across Distributions

• Majority of servers come with default shell environments for interacting with Linux OS.

• Shell commands are consistent across various Linux distributions.

Practical Application: Creating Files via Command Line

Demonstrates how file creation differs between Windows GUI and Linux command line interfaces due to production server requirements.

File Creation Process

• Windows uses GUI for file creation; Linux relies on command line due to lightweight production server needs.

Class Introduction and Shell Scripting Basics

In this section, the instructor introduces the class and begins demonstrating basic shell scripting commands using a Mac laptop with bash installed.

Introduction to Shell Scripting

• The instructor recommends using bash for shell scripting due to its popularity and widespread usage in software development and DevOps.

• Demonstrates retrieving the IP address of an AWS instance created in a previous class to use for logging in, emphasizing the use of key-value pairs for authentication.

• Explains the SSH command syntax for logging into a server using an identity file and the public IP address, highlighting Ubuntu as a common distribution in Linux operating systems.

• Contrasts Linux distributions like Ubuntu, CentOS, Red Hat, Fedora, and Debian, emphasizing Ubuntu's prevalence. Introduces basic navigation commands in Linux compared to Windows operations.

Navigating Directories and Commands

This section focuses on essential commands for navigating directories in Linux systems.

Directory Navigation Commands

• Introduces the 'ls' command to list files and folders within a directory, emphasizing its role as a listing tool.

• Explains the 'pwd' command for identifying the present working directory (PWD), crucial for understanding one's location within the system.

• Demonstrates changing directories using 'cd' command akin to navigating between directories on Windows but through text-based commands rather than graphical interfaces.

Advanced Directory Navigation

Building upon basic navigation commands, this section delves into more complex directory movements within a Linux system.

Advanced Navigation Techniques

• Highlights differences between Windows GUI-based navigation and text-based Linux navigation. Emphasizes PWD and LS commands before executing CD commands for effective directory changes.

Linux Command Line Basics

In this section, the instructor introduces basic Linux commands for navigation and file management.

Navigating Directories

• Understanding the CD command to move between directories.

• CD command is used to navigate between directories.

• Utilizing the slash operator (/) to move back or ahead through multiple directories efficiently.

• The slash operator facilitates moving back or ahead through multiple directories.

Listing Files and Folders

• Introducing the LS -LTR command to list files with detailed information like ownership, type (file/directory), permissions, size, and timestamps.

• LS -LTR provides comprehensive information about files and folders.

• Understanding how to differentiate between files and directories based on the output of LS -LTR.

• Files are identified by not starting with 'D' in the output of LS -LTR, while directories start with 'D'.

Creating and Writing Files

• Using the touch command to create a new file quickly.

• The touch command creates a new file instantly.

• Employing the VI command to create and write content into a file interactively.

• With VI, users can both create and write content into a file interactively.

Advanced Linux Commands

This part delves into advanced Linux commands, shell scripting basics, and real-world applications.

Shell Scripting Fundamentals

• Exploring comprehensive video tutorials covering shell scripting basics in detail.

• Detailed video tutorials cover fundamental shell scripting concepts extensively.

• Providing links for further learning on intermediate shell scripting topics.

• Additional videos focus on intermediate shell scripting concepts for deeper understanding.

Real-Time DevOps Projects

• Teasing upcoming classes discussing real-time DevOps projects utilizing shell scripting skills practically.

• Future classes will delve into real-world DevOps projects showcasing practical uses of shell scripting.

File Management Commands

• Demonstrating essential commands like mkdir for creating directories and RM for removing files or directories.

Understanding System Properties in Windows and Linux

In this section, the speaker discusses how to check system properties in both Windows and Linux operating systems.

Checking System Properties in Windows and Linux

• To check system properties on a Windows machine:

• Access system properties to view RAM size.

• Use Task Manager to determine RAM usage.

• Compare RAM size from system properties with actual usage in Task Manager.

• To check system properties on a Linux machine:

• Utilize shell commands for memory and CPU information.

• Use free command for memory details.

• Employ nproc command to ascertain the number of CPUs available.

• Understanding disk size:

• Use DF -H command to determine disk size and usage percentages.

• Monitor overall system information using the top command for CPU, memory, and disk details.

Managing System Resources Efficiently

This part focuses on managing system resources effectively through various shell commands.

Efficient Resource Management

• Popular shell commands for daily use:

• Utilize top command for comprehensive monitoring of CPU, memory, and disk usage.

• Specific commands for different resource aspects:

• Use free command for memory management.

• Employ nproc command for CPU-related tasks.

• Check file sizes with the DF command.

Exploring Further Learning Opportunities

The speaker introduces additional learning resources related to shell scripting.

Additional Learning Resources

• Accessing educational content:

• Explore videos on the channel covering intermediate-level shell commands.

• Future topics:

• Preview upcoming real-time shell scripting DevOps project discussion scheduled for tomorrow's session.