IT 136 – Intro To Linux

1. Class Details: M/W 7:15pm-9:15pm Room: 3183 nathaniel.dillon@seattlecolleges.edu IT 136 – Intro To Linux

2. Me • Took community college courses to transfer into a 4-year college • After graduation, did security programming at the Chicago Board of Trade (Java/C/C++/Bash) • Moved on to manage the Security Intrusion Detection Systems for BlueCross BlueShield, moved internally into Linux/Unix administration • Traded that in for hardware and Linux administration, been doing that for about six years now • Moved out here four years ago with my wife for admin job (so email responses will not be instant)

3. Syllabus • The short version: We’re all adults, you’re paying for this time, I expect you to act as such; respect each other, me, and the class and we will get along • I do take attendance (worth one assignment in total) • Class is split between lecture and in-class exercises • I start taking and don’t stop until the ‘practical’ exercises • If you need a drink/etc…, go for it; if you need a day or two off, go for it – however: • I expect you to be responsible for any work/info you miss • I post notes/lectures/homework online and answer questions, I cannot make you learn it

4. For Experienced Users • If you can write a Bash script within 48 hours that: • Has your name and today’s date as a comment • Prints your username to STDOUT • Checks if username is in sudoers file • Starts a sleep(1000) command in the background • Checks if Apache is installed via RPM • Attempts to start Apache • Runs regex against the Apache config file that checks for the ‘default’ documentroot • Redirects the output to a file in /tmp • Kill the sleep(1000) command using job # • Come talk to me, this class is going to bore you

5. First • This class is challenging • Linux is a different perspective and interaction • I add stuff that’s generally IT related • You will get new material every class • Sometimes LOTS of new material • I add new stuff on quizzes • ie, if I tell you how to look up any command to find out what it does, I will expect you to be able to do that with a new command that you haven’t seen before • You will need to study on your own, probably for about an hour per class

6. Class Format • I talk for about an hour introducing new material • An in-class practical is issued for you to work on the new material with me available as a resource • Homework is issued that is due before class starts the next class day • Tests and quizzes based off homework and ‘practical’ walkthroughs • Practicals have default usernames as well as most commands used

7. Class Webpage • Everything will be posted on the website for the class • Everyone will receive an email from me, this email will contain the link to the class webpage • Presentations, practicals, homework, additional handouts, etc… will all be posted there for the duration of the course • This is where you can go if you miss a day and need to review what we went over that day • Assignments are to be emailed to me or in my hand by the time class starts

8. Virtual Machines • We use virtual machines (vm’s) – VMWare Workstation (I like VirtualBox) hypervisors • This is a program that simulates an entire computer (or group of computers) • It will react exactly as if it is a real computer • It uses files as ‘hard drives’ and VMWare mimics the hardware responses • Start up a VM, click inside, push ctrl and alt keys at the same time to get out • This is “the cloud” (for real)

9. Your Three Best Friends • The book is not required • It is a good intro/overview, and also contains advanced topics, but is not necessary • Your three best friends in this class are • Search engines • The command line • Reference books

10. BF1: Search Engines • Useful When: you catch a keyword, or I ask you a general question • Ex1: “What is the Linux command to show the system’s IP address?” • I would ask you this on a practical/homework/test • Ex2: “linuxip address” • This is something you would put into a search engine looking for the answer to ex1

11. Aside 1 – Google’ing • If I ask you “What is the command to show an IP address in Linux?” • Do NOT type that whole question in • Google works on keywords, and how many people link web pages to other pages with those keywords • Keywords? • What about: • Where are users directories located in CentOS?

12. BF2: The Command Line • When you’re on a system, you can use ‘manual’ pages to find out what a command does, what it needs, and how you can change its behavior with ‘flags’ • Ex1: What does the ifconfig command do? • Type man ifconfig to find out it displays the IP address and interface info on a Linux system • The shell will try to tell you if/where an error is based on the error messages • Pay attention to error keywords and our model

13. BF3: Reference Materials • Primarily used when a concept is not understood or the internet is not available • When I'm incomprehensible • I like coffee and speak quickly when over-caffeinated • I use Sobell’s book because the ‘on-system’ manual pages are done at ‘best effort’ • Sobell consistently goes through and more concisely and thoroughly explains commands, flags, options. This is the last part of the book.

14. Own Study • I try to include a slide at the end of each lecture that highlights the topics we discussed today as well as the relevant sections in the book so that you can go into the book and materials to study on your own • You will need to study on your own • Did I mention this class was challenging? • http://explainshell.com/ • I just found this one, tell me if you like it

15. Hopefully You Already Know • These terms • Kernel, operating system, application, hardware, hard drive, command, command line, folder, file, path, IP address, server, web server • If you can use your own words to describe those, you have a good base for this class • If you do not know what those are, please research them, I will talk about them like you already know them • Tonight’s homework and practical are baselines

16. Your Questions • While the book is not necessary, my goal is to prepare you for a ‘corporate’ environment • If you ask me a question, I will respond with “what does Google say?” or “what does the book say?” or “what did you get when you tried it?” • I probably will send you back to try it yourself – it is the best way to learn it; if there's still a question after that, I will answer it • That is also probably more nice than what anyone would do in a corporate environment • To that end, assignments will get more vague as the semester goes on – that is intentional

17. Failure • Is extremely important • A good boss said: “It’s okay to make mistakes; it’s not okay to repeat them” • IMPORTANT: Throughout the guided practicals I leave off ‘sudo’ or general parts of commands • This means commands partially work but also partially fail • It’s important to see what this does in a safe environment so that when you err in a corporate environment (and it WILL happen), you can realize it and fix it

18. Questions? • Questions on course layout? • Ready to get into Linux?

19. Intro to Linux • Linux is a “catch-all” term that covers programs that use the Linux kernel • The Linux kernel is packaged by different groups and released as different ‘flavors’ such as RedHat, CentOS, Debian, Ubuntu, Android, Slackware, Gentoo, Mandriva, Backtrack, and many more • We will look at CentOS Linux through the command line • The GUI is nice and makes life easier but also hides everything

20. Operating System • Operating system is “a set of software that manages computer hardware and provides common services for computer programs” (wikipedia) • It’s what allows the hardware to run programs • Windows is an ‘overarching term’ that covers several operating systems – 3.1, ‘95, NT, XP, 2k3, Vista, 7, 8, 2012 • Linux is similar – overarching term that covers RedHat, Ubuntu, SuSE, Slackware, Backtrack, CentOS, Debian, etc…

21. Windows

22. Linux OS (Gnome)

23. Linux OS (KDE)

24. Linux OS (Unity/Weyland/Something?)

25. Linux Command Linux (Us)

26. Linux • Linux kernel is actually the ‘brains’ of the operating system • Wikipedia: the kernel “is a bridge between applications and the actual data processing done at the hardware level” • Hardware: chassis, cd/dvd, motherboard, processor, memory, harddrive, power supply, extras • Application – program that runs on a computer (MS Word, InternetExplorer/Firefox, Outlook) • Data processing – processor’s ‘adder’ gates

27. What? • Example: Firefox (or IE, or Chrome) • Runs in a window with our Desktop behind it (in our case – ‘current working directory’) • Behind the scenes: software making sure power supply is providing power, fan is running • Also: saving files from the internet • Opening a socket on local system, initiating handshake, receiving incoming info stream, translating stream to temp file, moving temp file to file name you saved it as, telling you file was saved • The kernel handles all that so you don’t have to!

28. History – Unix to Linux • Unix operating system was created at AT&T • LinusTorvalds published his version (not directly Unix derivative, but very close) in 1991 • Requested others to help add to it; is now Linux • Current corporate 'standards' are RHEL and SuSE • Today we will talk about Linux, installations and 3 file channels • Wednesday we will review this info; next week we will start moving very quickly

29. Linux • Linux has several versions, but we will be using CentOS • Android and Ubuntu are based off Debian • CentOS and many others are based off RHEL or RedHat Enterprise Linux • CentOS and RHEL are “binary comaptible” – meaning the binary (0’s and 1’s) level code matches, except where they said it was “RHEL” they switched to “CentOS” (& some specific apps) • If you have CentOS on a resume, you can also have RHEL

30. Linux, pt2 • CentOS has a nice graphical-user interface • We are not going to be using it • This class will be focused on the ‘command-line’ • [student@it136centos58vm ~]$ • This is the command prompt, command line or shell (all the same thing) • The above is the power in Linux • Above shows user, hostname, current directory, and allows for input

31. Major Paradigm Shift • Windows is all GUI – you are always in your “Desktop” directory • Linux is ‘command line’ – all typing, you change directories • No desktop – no clicking • You are in whatever directory you enter • Default login is ‘home directory’ • Usually /home/<user> • In desktop – you can always click desktop icons • In command-line, moving to a new directory changes where you are

32. File Path • In this new paradigm, file paths are important • File Path: Where something is located on a system • Linux has one ‘top level’ directory, everything else is below that • Top level directory is / • All other directories exist ‘below’ this directory • This means all directories are connected, and you can map a path from one point on the system to any other point (file/directory/resource/etc)

33. Login • Most medium to large sized companies will have a low-access user the whole group uses and then escalates to root (Admin) • Ours is student and the password is Pug3t$ound! • The shell will display • [student@it136centos58vm ~]$ • Today, we will go over VMWare and a Linux installation

34. Recommendation • If you need to learn Linux, use it as your primary OS (Ubuntu almost always 'just works') • If you can't (shared/corp laptop), consider Cygwin • VM's (VMWare or VirtualBox) allow you to have a Windows installation if you need it, or allow you to have Linux inside your Windows installation • If you had not heard of those terms, do the homework/practical from today

35. Questionsand Installs • Homework and practical will review terms • Don't forget to turn in your info sheet • Questions?