Davi Orlandi

Posted on Dec 14, 2025 Edited on Oct 5

Getting Started With Linux

#linux #devops #webdev #distributedsystems

This article is a study-oriented, introductory overview of Linux. It covers basic concepts and simplifies some topics to help beginners build an initial mental model — a starting point, not an exhaustive reference.

Base needed knowledge:

GNU: GNU is a predecessor of Linux and a free open-source Unix-like operating system.

Kernel: The kernel is the core of an operating system. It acts as a bridge between software and hardware, managing system resources (CPU, memory, peripheral devices). Although people use "Linux" to describe the whole operating system, Linux itself refers only to the kernel.

What is Linux?

Linux is an open-source operating system kernel originally created by Linus Torvalds. In practice, when people say "Linux," they usually mean a complete operating system: the Linux kernel combined with tools, libraries, and other software from the GNU project.

A Linux system is divided into three layers:

Hardware: The physical resources of your machine — CPU, memory, peripheral devices, etc.

Linux Kernel: The core of the operating system. It manages the hardware and facilitates communication between software and hardware.

User Space: The environment where users interact with the system, using applications and command-line interfaces.

What is a Linux distribution?

A distribution is a bundle of the Linux kernel with specific software, tools, system utilities, libraries, and applications. Essentially, a distro is a complete, ready-to-use operating system built around the Linux kernel.

Debian:

Debian is an operating system composed entirely of free and open-source software, and one of the most respected projects in the community.

Package Management

Debian uses a powerful package management tool called apt (Advanced Package Tool). The system maintains a massive repository of pre-compiled software packages.

Red Hat Enterprise Linux (RHEL)

RHEL is a commercial Linux distribution developed by Red Hat, built to provide long-term stability, security, and professional support.

Package Management

RHEL uses the RPM (Red Hat Package Manager) format for its software packages. For managing those packages, it provides package managers like YUM (Yellowdog Updater, Modifier) and its successor, DNF (Dandified YUM).

Ubuntu

Ubuntu is probably the most famous Linux distribution — an excellent entry point for anyone looking to get started with Linux.

Package Management

As a Debian-based operating system, Ubuntu uses the core Debian package management system. That means it uses the apt (Advanced Package Tool) command-line utility to handle software installation, updates, and removal, giving users access to a vast repository of free and open-source software.

Fedora

Fedora is roughly Ubuntu's counterpart from the Red Hat side — built on Red Hat's foundation instead of Debian.

Package Management

Fedora uses the RPM package format and manages software with the DNF (Dandified YUM) package manager. DNF is a command-line tool for installing, updating, and removing software packages.

The shell

The shell is a program that accepts your typed commands and passes them to the operating system. If you've used a GUI (Graphical User Interface), you might have encountered applications like "Terminal" or "Console" — those are simply programs that open a shell session for you.

BASH (Bourne Again Shell)

Bash is the default shell for most Linux distros. While other shells like ksh, zsh, and tcsh exist, mastering Bash provides a solid foundation for working with any Linux system.

When you open a terminal, you'll see the shell prompt. Its appearance can vary between distros, but it typically follows this format: username@hostname:current_directory$.

Yeah, I used a MacOS Terminal screenshot — don't care, it's not relevant.

The $ symbol at the end indicates that the shell is ready to accept commands. You do not type this symbol when entering commands — it is purely informational!

How the hell does this work?
Just paste this command echo "I love Linux" and you'll see "I love Linux" as the output in the console.

Filesystem basics

Linux uses a single root filesystem, meaning everything starts from / (root). There are no drive letters like C: or D: — all storage devices are mounted into the same tree.

Common directories

/ — root of the filesystem
/home — user home directories
/etc — system configuration files
/var — variable data (logs, cache, spool)
/usr — user-installed software and libraries
/bin and /sbin — essential system binaries

In Linux, everything is treated as a file, including devices, processes, and sockets.

Paths

A path is the location of a file or directory inside the filesystem. It tells the system where something is in the directory tree.

Absolute paths start from /, like /home/user/projects. Relative paths omit the leading slash, like projects/my-app.

Useful navigation commands:

pwd   # show current directory
ls    # list files
cd    # change directory

Permissions & users

Linux is a multi-user operating system, built with security in mind from the start. Every file and directory has an owner, a group, and a set of permissions.

You can see permissions on your computer with ls -l:

Root is the superuser, with full access. Normal users have limited permissions. You can run commands as root by prefixing them with sudo.

Permissions are a core concept in Linux and one of the main reasons servers are secure by default.

Networking basics

Linux provides built-in tools to inspect, debug, and interact with networks. Networking is a fundamental skill, especially for servers, containers, and cloud environments.