• Tuesday, September 9, 2025

Intro to Linux and FOSS

Presented to you by the

The Shell

The shell is a command line-interface (CLI) to interact with a computer.

Common shells include: bash, zsh, fish

Tip: if you don't know if you're using zsh or bash, run echo $0

Basic command structure: [command] [flags] [arguments]

• ex: ls -a ~/
  • ls: lists the contents of a directory
  • -a: do not ignore entries starting with .
  • ~/: your user's home directory

Common shell commands:

• cd - change directory
• ls - list directory
• cat - concatenate and print files
• head - read the first 10 lines
• less - read larger files
• mv - move
• cp - copy
• rm - delete a file

And so many more... if you don't know the command for something, look up "how to ___ linux".

• ex. I want to unzip a file. Search "how to unzip a file linux", check Stack Overflow and see that you use the "unzip" command. Realize I don't have the unzip utility installed. Install it with my distro's package manager, profit.
• The common shell commands above are part of the "GNU Core Utilities"

Text Editors

• Vim
• Nano
• Emacs

You'll learn more in today's lab.

How did linux come to be?

GNU/Linux: Linux is the kernel of the OS, GNU is other crucial software (ex. Gnu Coreutils)

Licenses

You're looking at someone's code, when you see this weird "LICENSE" file...

github.com/nims11/IPod-Shuffle-4g

Or, you've created a repo on github and seen the "Choose a license" option.

Free vs. Open Source

Free Software

Richard Stallman (developer of GNU software and founder of the Free Software Foundation) - if you used gcc for 61c or the "ls" and "cd" commands, you used this man's stuff.

He's a bit...quirky. Here is his website: stallman.org

Free software allows its user to...

1. Run the software
2. Change the software
3. Redistribute the software
4. Redistribute the software with changes

Free Software, Free Society TED Talk

To promote this idea, the GPL license was created.

GNU General Public License (GPL)

"Viral" license: copyleft licenses are sometimes called "viral" licenses. This is because any derivative works must also be free software, so the copyleft license spreads like a virus. This can discourage people from using your projects in their own, possibly sabotaging the impact of your work.

"You": an avid copyleft advocate, also sometimes called "annoying to be around" and "probably suuuuper fun at parties".

What if I don't care about all this copyleft stuff and what people do with my code?

MIT License

MIT License

Copyright (c) [year] [fullname]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

True freedom. Live, laugh, kumbaya.

"Cuck" license: permissive licenses are sometimes called "cuck" licenses— because you risk a big company taking what you made and making it proprietary. They'll bottle your water on AWS and sell it right back to your friends, family, and waifu. You cuck.

hacker news post w/ gentoo wiki article

What about BSD and other licenses?

Not enough time. But check out choosealicense.com if you're confused or want more options.

Jaysa, why should I bother with all this license stuff? I just wanna make cool things.

I claim that you are broke in multiple ways.

P.S. If this isn't true, hop on over to ocf.io/donate and give us all of your money pretty please 👉👈

1 - You are too broke to have a company rip off your personal projects that you poured your blood, sweat, and tears into.

See the case of the creator of MINIX and Intel's IME chip.

2 - You are too broke to get fired or sued right now.

Still getting figured out this year:

"Modern smart TVs come with software that tracks viewing habits to deliver targeted advertising directly on the TV screen. Software Freedom Conservancy purchased a Vizio TV to develop an open-source version of the operating system that was more customizable and didn't track users to show them ads. This Vizio TV runs on Linux, an operating system that legally requires manufacturers to share the code that lets users customize their devices. When SFC asked Vizio to provide the complete, corresponding source code (“CCS”), they refused. SFC sued Vizio in the Orange County Superior Court to receive this essential information." - Software Freedom Conservancy

So, let's come back to our ipod shuffle python script.

github.com/nims11/IPod-Shuffle-4g

Examples

Situation 1

I use this script in a plugin I create for ncmpcpp, a terminal-based music player. I distribute it under GPLv3, a newer GPL license, instead of GPLv2.

WE ARE GNU + OK!!!

"This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version." - GPL 2.0

Situation 1 Part 2

I'm feeling nostalgic... I switch the license to GPLv1 instead because they just don't make them like they used to.

WE ARE GOING TO JAIL!!!

I use this script in a plugin I create for ncmpcpp, a terminal-based music player. I distribute it with the GPLv3 instead of GPLv2.

Situation 2

I fork the ipod-shuffle-4g repo and modify it so that it works for earlier versions of the ipod shuffle, too. I publish the code on github and forget to include a license at all.

WE ARE GOING BACK TO JAIL!!!

I distributed a modified version of the code (by making it publicly available) without it being under a GPL-compatible license. Copyleft/"Viral" nature of the license comes into play here.

Situation 3

I create a piece of software under the MIT license with publicly available source code. However, I need some money, and no one's sponsoring me because it turns out my code is allegedly "less crucial to infrastructure than the Linux kernel".

So, I create a private fork which contains extra features and only give access to people who sponsor the project.

WE ARE SPONSORWARE!!!

Proprietary, since users would only have freedom #1.

See mkdocs material's license

Also see the open-core model

Situation 4

I create some cool database software under the AGPL license.

“The GNU Affero General Public License [...] requires the operator of a network server to provide the source code of the modified version running there to the users of that server. Therefore, public use of a modified version, on a publicly accessible server, gives the public access to the source code of the modified version.”

My software is great and people love it! But big tech companies find a loophole. Someone in a consulting club graduates and comes up with a great idea for Amazon/Google Cloud/Azure: host my software on their platform and charge for it. I've been screwed over by SaaS - software as a service.

WE ARE MONGODB!!!

This is why the Server Side Public License (SSPL) was then created. Under SSPL, cloud providers would have to open source the software and APIs the user needs to run an instance of MongoDB themselves.

www.mongodb.com/legal/licensing/server-side-public-license

If all of this interests you, look into the field of software & data privacy law!