anarsec.guide/content/posts/linux/index.md

+++
title="Linux Essentials"
description="The Basics Needed to Use Tails or Qubes"
date=2023-04-04

[taxonomies]
categories = ["Defensive"]
tags = ["intro", "linux", "tails", "qubes", "easy"]

[extra]
blogimage="/gifs/destroy.gif"
blogimagepng="/images/destroy.png"
toc=true
dateedit=2023-05-10
a4="linux-a4.pdf"
letter="linux-letter.pdf"
+++

As an anarchist, you've probably heard the recommendation to use a Linux computer. This article is intended to get you started by giving you a brief overview of what you need to know. 
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# What is Linux and Why Use It? 

If you are reading this, you are probably using either Windows or macOS on your computer. These are both [operating systems](/glossary#operating-system-os), which is the system software that runs your device. They're also both "closed-source", which means that the software's "*source* code" is not available (*closed*) to the public, so it can't be audited for privacy and security. Windows and macOS computers send your data to Microsoft and Apple, and you can't trust their [full-disk encryption](/glossary#full-disk-encryption-fde) to protect your data if the computer is [physically accessed](/glossary/#physical-attacks) (like after a [house raid](https://www.notrace.how/threat-library/techniques/house-raid.html)). 

Linux is a set of operating systems that are [open-source](/glossary#open-source), which means that the *source* code can be analyzed by anyone. Linux is the name given to the core (**kernel**) of the operating system, and many different **distributions** (or 'distros') are based on it. Simply put, *Linux is the only type of computer that anarchists can trust*. 

Linux distributions that anarchists are likely to have heard of are Debian, Ubuntu and [Tails](/tags/tails/). Each Linux distribution makes different choices about how to manage software, what kernel version to use, etc. In fact, both Ubuntu and Tails are adaptations of Debian for the specific use cases of being user-friendly (Ubuntu) and providing anonymity (Tails).   

# How Software Works

In Linux, the term for an application is a **package**. Instead of downloading applications from various sites on the Internet (as in Windows and macOS), a Linux distribution has a centralized **repository** where the software lives. This has the advantage that the integrity of the software is verified by the distribution, and it is guaranteed to work with that Linux distribution. It is still possible to install software from outside of a distro's repository, but it is generally considered riskier, and verifying the integrity is your responsibility. Installing a package requires knowing its name, and all packages in a repository can be browsed using a web browser for both [Debian](https://www.debian.org/distrib/packages#search_packages) and [Fedora](https://packages.fedoraproject.org/).

How do you actually install from a software repository? Each distribution also has a **package manager**, which is an application that installs software from a software repository. Debian and distributions based on it use the `apt` package manager. In some distributions, it is possible to install software with a Graphical User Interface (GUI) that uses the package manager in the background, such as the [Synaptic Package Manager](/posts/tails/#installing-additional-software) in Tails. 

# Software Alternatives

Part of the learning curve for Linux is figuring out which open-source software to use instead of the closed-source options you are used to in Windows and macOS. For example, instead of using Microsoft Word, you might use LibreOffice. The fact that an application is open-source is an essential criterion, but it is not enough to be considered secure. For example, Telegram advertises itself as open-source, but the servers are not open-source and the cryptography is [garbage](https://buttondown.email/cryptography-dispatches/archive/cryptography-dispatches-the-most-backdoor-looking/). The list of [included software for Tails](/posts/tails/#included-software) will cover many of your needs with reputable choices, and you can also check out [switching.software](https://switching.software/). 

# The Command Line Interface

![](cli.png)

The dreaded [command line](/glossary/#command-line-interface-cli)! What even is it? You are used to interacting with applications through a **Graphical User Interface (GUI)**, which means pointing and clicking buttons with your mouse. Some applications can also be interacted with through a **Command Line Interface (CLI)**, which is textual. Many applications are available in both CLI and GUI versions. 

For example, navigating the contents of your computer with the File Manager GUI is pretty standard - you click on a folder (called a *directory* in Linux), and it opens. The same navigation through the file system is also possible from the CLI.

When you open a Terminal (the CLI application), you get a *prompt*. It is called a prompt because it is prompting you to say something in a language that the Terminal understands. Prompts differ in what information is displayed, but they all end with the `$` character. You then give *commands* to the Terminal. The Terminal responds, then redisplays the prompt to take more commands.  

The best way to learn the basics of the command line is to interact with it. We recommend the [Foundations: Linux Journey](https://techlearningcollective.com/foundations/linux-journey/the-shell) exercise to learn some basic commands. The [Software Distribution and Packages](https://techlearningcollective.com/foundations/linux-journey/software-distribution) exercise will teach you what you need to know to [install software in Qubes](/posts/qubes/#how-to-install-software).  

Some commands require elevated privileges, equivalent to "Open as Administrator" in Windows. For example, installing software usually requires this. Prefixing a command with `sudo` will execute it as the administrative user, named root (note: the root user is not the same as the root directory, and the two should not be confused). A root prompt will display `#` instead of `$`. Be especially careful with any commands you run while using these elevated privileges, as you'll have the power to erase your entire hard drive or change important files. It is helpful to know that text is pasted in the Terminal with Ctrl+Shift+V (i.e. the Shift key must also be pressed). 

Most Linux users will rarely need to use the CLI. If you're using Tails, you shouldn't need it at all. If you're using Qubes OS, the CLI is only needed to install software:

* `apt install <PACKAGE_NAME>`: this will install packages on Debian 
* `dnf install <PACKAGE_NAME>`: this will install packages on Fedora 

Additionally, the CLI is needed for the more secure installation of both [Tails](/posts/tails-best/#appendix-3-gpg-explanation) and [Qubes OS](https://www.qubes-os.org/security/verifying-signatures/) to verify the download's authenticity. 

If you ever don't understand what a command does, try searching [explainshell](https://explainshell.com/) for it.

# Going Further

If you want to learn more about Linux, we'd recommend:

* The rest of the Tech Learning Collective's [Foundations](https://techlearningcollective.com/foundations/) exercises will give you a much more comprehensive foundation than what you need to use Qubes or Tails.  
* [Linux Fundamentals at Hack The Box Academy](https://academy.hackthebox.com/course/preview/linux-fundamentals) is another interactive learning environment with a less comprehensive overview.