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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)
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
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
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
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
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
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)
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
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: “linux ip address” This is something you would put into a search
engine looking for the answer to ex1
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?
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
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.
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
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
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
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
Questions?• Questions on course layout?
• Ready to get into Linux?
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
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…
Windows
Linux OS (Gnome)
Linux OS (KDE)
Linux OS (Unity/Weyland/Something?)
Linux Command Linux (Us)
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
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!
Unix operating system was created at AT&T Linus Torvalds 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
History – Unix to 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
Linux
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
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
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)
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
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
Questions and Installs
Homework and practical will review terms Don't forget to turn in your info sheet Questions?
