Linux architecture Notes

Added comprehensive notes on Linux operating system, covering its components, distributions, installation methods, process states, and commonly used commands.

Refactor and clarify sections on Linux OS components, distributions, and process states.

Added a comprehensive cheatsheet for Linux commands, including usage and examples for various commands related to file management, user management, and system information.

Updated the Linux commands section and improved formatting.

Removed redundant 'Goals -' and 'Core DevOps Skills -' prefixes for clarity.

Updated current level description for clarity.

Documented various Linux process management commands including ps, top, and kill with examples and descriptions.

Updated Linux practice document with detailed command descriptions and examples for process management, memory usage, and disk space.

Added system management and logging commands to the Linux practice guide.

Added detailed troubleshooting steps for Linux server performance issues, including service/process checks, resource snapshots, and immediate actions.

Added detailed troubleshooting steps and observations for the OpenSSH Daemon (sshd).

Added a comprehensive troubleshooting runbook for Docker incidents, including steps for CPU and disk pressure investigations, immediate containment actions, and escalation triggers.

Documented a comprehensive troubleshooting runbook for nginx failures, including steps for simulating, diagnosing, and resolving issues.

Added a comprehensive NGINX troubleshooting runbook covering incident types, simulated failures, environment checks, and recovery steps.

Added a comprehensive runbook for troubleshooting database failures, including steps for PostgreSQL and nginx rate limiting scenarios.

This cheat sheet provides a quick reference for emergency on-call procedures, including system checks, logs, common containment actions, and troubleshooting steps for various services.

Added detailed explanations of the Linux file system hierarchy and provided scenario-based practice steps for managing the nginx service.

Documented the setup process for Nginx and web deployment on an EC2 server, including screenshots of key steps.

Added group assignments, created directories, and listed commands used for user and group management.

Documented file permissions and operations for Day 10 challenge, including created files, permission changes, commands used, and lessons learned.

Added detailed information about networking fundamentals, including OSI and TCP/IP models, troubleshooting commands, and hands-on checks.

Added detailed explanations of networking concepts including DNS, IP addressing, subnetting, and ports.

Added a comprehensive guide on shell scripting basics, including examples of scripts for variables, user input, conditional statements, and service checks.

Added comprehensive documentation on shell scripting covering loops, command-line arguments, error handling, and package installation.

Added a comprehensive guide on shell scripting, covering functions, return values, strict mode, local variables, and a system info reporter script.