Linux

Here are some common Linux distributions (distros) that I know or have been widely used:

1.      Ubuntu

·         Use: One of the most popular distros, known for its user-friendliness and ease of useIdeal for beginners and widely used on servers and desktops.

·         Example: Ubuntu Desktop, Ubuntu Server.

2.      CentOS

·         Use: A free and open-source version of Red Hat Enterprise Linux (RHEL)Popular in enterprise environments for servers.

·         Example: CentOS 7, CentOS Stream.

3.      Debian

·         Use: Known for its stability and large repository of softwareOften used as the base for other distributions like Ubuntu.

·         Example: Debian 10 (Buster), Debian 11 (Bullseye).

4.      Fedora

·         Use: A cutting-edge, community-driven distro sponsored by Red HatKnown for incorporating the latest features and technologies.

·         Example: Fedora Workstation, Fedora Server.

5.      Arch Linux

·         Use: A lightweight and flexible distro for advanced usersIt follows a rolling release model, meaning it gets continuous updates.

·         Example: Arch Linux installation.

6.      Linux Mint

·         Use: A user-friendly distro based on UbuntuKnown for its simplicity and a good alternative to Windows.

·         Example: Linux Mint Cinnamon Edition.

7.      Red Hat Enterprise Linux (RHEL)

·         Use: A commercial version of Linux used primarily by businesses and enterprises for server environments.

·         Example: RHEL 8.

8.      SUSE Linux Enterprise Server (SLES)

·         Use: A commercial distribution used mainly in enterprise environments, known for its reliability and enterprise-grade support.

·         Example: SUSE Linux Enterprise Server 15.

9.      Kali Linux

·         Use: A security-focused distro used for penetration testing, ethical hacking, and digital forensics.

·         Example: Kali Linux 2023.

10.  Manjaro

·         Use: A user-friendly version of Arch Linux, offering the power of Arch with a more accessible user experience.

·         Example: Manjaro KDE, Manjaro XFCE.

Red Hat and its derivatives use YUM (Yellowdog Updater, Modified) or DNF (Dandified YUM) for package management.

Ubuntu and Debian-based systems use APT (Advanced Package Tool) for package management.

This process assumes that the system's package manager is configured to pull from the default repositories. If you need to install from third-party repositories or manual package files, the steps may differ.

The Linux kernel is the core part of a Linux operating system. It acts as a bridge between the hardware (the physical components of your computer) and the software (the applications and processes running on the system).

Types of Kernel:

1.      Monolithic Kernel: The Linux kernel is a monolithic kernel, meaning it contains all essential services like process management, file system handling, and device drivers in one large block of code.

2.      Modular Kernel: The Linux kernel can load modules (like drivers) dynamically, meaning you can add or remove functionality without rebooting the system.

Summary:

The Linux kernel is the heart of a Linux-based operating system, responsible for managing hardware, system resources, and providing a secure environment for software to run.

A Kernel Module is a piece of software that can be added to the Linux kernel to provide additional functionality, such as supporting new hardware or features, without the need to modify or reboot the entire kernel.

The Linux file system is a hierarchical directory structure where files and directories are organized in a tree-like structure. The root directory (/) is at the top of this hierarchy, and all other files and directories are contained within it.

·         /bin: Essential system commands.

·         /boot: Boot files.

·         /dev: Device files.

·         /etc: Configuration files.

·         /home: User home directories.

·         /lib: Shared libraries.

·         /media: Removable media mount points.

·         /mnt: Temporary mount points.

·         /opt: Optional software.

·         /proc: Process and system information.

·         /root: Root user’s home directory.

·         /sbin: System binaries.

·         /srv: Service data.

·         /sys: Kernel and system information.

·         /tmp: Temporary files.

·         /usr: User programs and utilities.

·         /var: Variable data, logs, and mail.

This hierarchical structure makes it easier to organize and manage the system while ensuring that each directory serves a specific purpose for both the operating system and the user.

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To change the permissions on a file in Linux, you can use the chmod command. This command allows you to modify who can read, write, or execute a file.