Introduction​​ to​​ UNIX,​ the​​ shell,​ OSS

mdcha

(slides stolen heavily borrowed from mdcha Loren McIntyre)

ocf.io/decal/slides/1

Topics today - 2018-01-30 Tuesday

• Course logistics
• Intro to the shell
• History of UNIX
• Free and Open Source Software

Logistics

• 8-9pm in OCF Lab; Tuesdays: Beginner Track
• Attendance is mandatory (+/- 2). Lecture doubles as office hours / lab time
• Don’t copy solutions (But feel free to work together!)

Course resources

• Your facilitators!
• Join you a Piazza - https://ocf.io/decal/piazza
• All the material (new and old) is online!
• Syllabus - will be posting a schedule with links on the home page

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Shell

• What is the shell? A command line-interface (CLI) to interact with the computer.
• Common shells: bash, zsh, fish
• They’re mostly the same, (bash will be supported by almost all UNIX systems though).

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Shell

• Level 0 understanding: type things, get results
• Level 1 understanding: execute programs by name & shell builtin-functions, “shell” collects and shows you results
• Level 2 understanding: run interactive programs, replacing the shell interface with another program which parses your input

Editors

• Nano
• Vim (`vimtutor`)
• Emacs (Emacs Tutorial)
• NotePad

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Shell Commands

• Basic structure of a command is `[command] [flags] [arguments]`

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• RTFM! `man command`
• Google is also your best friend.

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

Evolution of UNIX

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GNU and the Free Software Movement

“So that I can continue to use computers without violating my principles, I have decided to put together a sufficient body of free software so that I will be able to get along without any software that is not free.”

Richard Stallman (1983)

https://groups.google.com/forum/#!msg/net.unix-wizards/8twfRPM79u0/1xlglzrWrU0J

Meanwhile at Berkeley...

• A UNIX derivative (BSD) was created at UC Berkeley
• Popular and reliable, a lot of things from BSD are used today
• vi and Berkeley sockets
• Stuck in legal limbo w/ AT&T
• BSD derivatives still remain popular (MacOS, FreeBSD, OpenBSD)

Unix’s advantages over non-Unix systems

• UNIX philosophy: simple, short, clear, modular, and extensible code
• UNIX idea: “everything is a file”
• Worse is better.
• Sockets for networking, now copied beyond Unix systems
• “It’s very simple — you read the protocol and write the code.” - Bill Joy on implementing TCP/IP

Open Source Software (OSS)

Free and Open Source Software (FOSS) or Free/Libre Open Source Software (F/LOSS)

“Free as in beer, and free as in freedom”

Open source software - term used by some software and technology companies. You may not have the right to use, modify, or redistribute the software or source code.

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Why FOSS?

• Security
• Cost
• Privacy
• Control
• Collaboration

OSS Licenses: Legal Jiggery-Pokery

• Copyleft (GPL)
• “I want to make sure that all versions of GNU remain free.” - Stallman (GNU Manifesto)
• “a cancer that attaches itself in an intellectual property sense to everything it touches” - Steve Ballmer
• Permissive (MIT, BSD, Apache, WTFPL)
• Do whatever you want (basically)

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Resources

• ArchWiki
• TLDP (The Linux Documentation Project, tldp.org) guides: Bash scripting, System Administration
• The Art of Unix Programming
• Debian System Administrator’s Handbook
• Neal Stephenson - “In the Beginning was the Command Line”
• Over The Wire: Bandit
• Challenge Problem (Just for fun)
• Using `curl` (and `man`)...determine how many HTTP redirects it takes to get
• From http://ocf.io/decal
• To https://decal.ocf.berkeley.edu

decal.ocf.berkeley.edu/signin

liskov