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Components:

• Bootloader: A piece of code that runs to guide the booting process to start the operating system. Parrot Linux uses the GRUB Bootloader.
• OS Kernel: The kernel is the main component of an operating system. It manages the resources for system’s I/O devices at the hardware level.
• Daemons: Background services are called “daemons” in Linux. Their purpose is to ensure that key functions such as scheduling, printing, and multimedia are working correctly. These small programs load after we booted or log into the computer.
• OS Shell: The operating system shell or the command language interpreter (also known as the command line) is the interface between the OS and the user. This interface allows the user to tell the OS what to do. The most commonly used shells are Bash, Tcsh/Csh, Ksh, Zsh, and Fish.
• Graphics server: This provides a graphical sub-system (server) called “X” or “X-server” that allows graphical programs to run locally or remotely on the X-windowing system.
• Window Manager: Also known as a graphical user interface (GUI). There are many options, including GNOME, KDE, MATE, Unity, and Cinnamon. A desktop environment usually has several applications, including file and web browsers. 
• Utilities: Applications or utilities are programs that perform particular functions for the user or another program

The Linux operating system can be broken down into layers:

• Hardware: Peripheral devices such as the system’s RAM, hard drive, CPU, and others.
• Kernel: The core of the Linux operating system whose function is to virtualize and control common computer hardware resources like CPU, allocated memory, accessed data, and others. The kernel gives each process its own virtual resources and prevents/mitigates conflicts between different processes.
• Shell: A command-line interface (CLI), also known as a shell that a user can enter commands into to execute the kernel’s functions.
• System Utility: Makes available to the user all of the operating system’s functionality.

Linux follows five core principles:

• Everything is treated as a file: All configuration files for the various services running on the Linux operating system are stored in one or more text files.
• Small, single-purpose programs: Instead of large, multi-functional applications, Linux relies on small utilities that each do one thing well, such as ls for listing files or cat for concatenating files.
• Chaining programs together: The output of one program can be easily used as the input for another through the use of pipes (|), allowing users to combine simple tools to perform complex tasks.
• Text as a Universal Interface: Linux tools use plain text for configuration and communication whenever possible. Text is simple, portable, and human-readable. Configuration files like /etc/passwd or /etc/hosts are just text.
• Avoid captive user interfaces: Linux is designed to work mainly with the shell (or terminal), which gives the user greater control over the operating system.