CST8207 Week 02 Notes
the shell, arguments and options, man pages

Ian! D. Allen – www.idallen.com

Winter 2018 - January to April 2018 - Updated 2018-02-28 18:56 EST

1 T Building Power Shutdown 9pm Saturday January 27 affects CLSIndexup to index

See your CST8207 Blackboard announcements for an important message regarding the power shutdown at 9pm on Saturday, January 27.

2 Student Feedback – How to Succeed in LinuxIndexup to index

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| | | | _____      __ |_   _|__   / ___| _   _  ___ ___ ___  ___  __| | (_)_ __   | |   (_)_ __  _   ___  __
| |_| |/ _ \ \ /\ / /   | |/ _ \  \___ \| | | |/ __/ __/ _ \/ _ \/ _` | | | '_ \  | |   | | '_ \| | | \ \/ /
|  _  | (_) \ V  V /    | | (_) |  ___) | |_| | (_| (_|  __/  __/ (_| | | | | | | | |___| | | | | |_| |>  < 
|_| |_|\___/ \_/\_/     |_|\___/  |____/ \__,_|\___\___\___|\___|\__,_| |_|_| |_| |_____|_|_| |_|\__,_/_/\_\

Some advice from CST student Joshua McNeely

“learn how to use the website early, because it is an incredibly useful resource (it’s the only resource needed).”

I encourage you to read the course notes. Don’t take my word for it:

Note from a student in 17W:

From: Damien Houle - CST8207-17W
Subject: Wonderful Website

I wanted to make sure you're aware of how much the students and myself
from last semester appreciate your awesome website. Many of us have
used it on multiple occasions throughout our level 2 course for
our current assignments because it has everything we need, as long
as we READ ALL THE WORDS! I really miss your labs and lectures and
realize now how spoiled I was to have you as my teacher and Linux
mentor. Hope the semester offers you as much fun as our class was
although i doubt it.
Best regards
Damien Houle (aka Linux people)

Note from a student in 17W:

Dear Professor Allen,
I was working with the mid-term practice last weekend, and it doesn't goes
very well. And then I go back to watch the class notes(I know! I should do
that in the first place) because I realize that I missed lots of the
information. Then I found that the pages of course notes are super helpful.
It helps me a lot!
I thought the pages are too much links and too complex when I just taking a
quick look in the first time, but I was wrong. It's so impressive that the
contents are strong logical, everything is explained in detail but not
complicated, easy to understand. Most of the things does not take me a long
time to understand.
I really should read the pages earlier!!!
It does takes me many time to adapt the new learning style as a foreign
student, but I am feeling better right now. Hopefully, it is not too
late for the test.
Anyway, just want to tell you that the course pages are very helpful. And
thank you, This is a great work for us!

Mail about the web site from the USA:

From: King, Alexander J
To: Ian Allen
Subject: Lecture cap inquiry
Date: Sat, 8 Apr 2017 05:22:52 -0400

Professor Allen,

My name is Alexander King and I'm a computer science engineering student
at The University of Toledo, Ohio. I came across a video of you rapping
the other day. I must say it was entertaining. After that I went on to
find your website <http://www.idallen.com/>. I'm writing to inquire if
any of your lectures have been recorded and if you're able and willing to
share them with me? Your <http://teaching.idallen.com> is amazing as it
is but I figured I would ask if actual lectures were out there somewhere.

All the best,
Alexander J King

3 Readings, Assignments, Labs, Tests, and ToDoIndexup to index

3.1 Read (at least) these things (All The Words)Indexup to index

  1. Week 02 Notes HTML – this file – Read All The Words
  2. File Transfer – File transfer to/from Unix/Linux machines. You need to know this this to upload your assignments for marking.
  3. The Unix/Linux Shell – using the shell command line in Linux
  4. Command Arguments and Options
  5. Finding Help in Manual Pages – RTFM
  6. File System and Pathnames – ROOT, absolute, relative, dot, dot dot
  7. List of Commands – Command names you should know, listed by week
  8. Linux and Sysadmin News in the World

3.2 Assignments this weekIndexup to index

Check the due date for each assignment and put a reminder in your agenda, calendar, and digital assistant. Just like in the Real World, not all due dates are on the same days or at the same times.

3.3 Lab work this weekIndexup to index

3.3.1 WorksheetsIndexup to index

Worksheets are preparation for your assignments. You can’t do the assignments without having done the worksheets first, and you can’t do the worksheets without having first read the Course Notes: 1. Read. 2. Worksheets. 3. Assignment.

Make notes from the worksheets on how each command works. What do the options used in the worksheets mean, for each command? (See the weekly List of Commands.)

Form a small study group to do the worksheets. Each person tries the example given, and you make sure you all get the same answers. Worksheets are not for hand-in; they are not worth marks; the assignments test your knowledge of the lectures and worksheets.

The worksheets are available in four formats: Open Office (ODT), PDF, HTML, and Text. Only the Open Office format allows you “fill in the blanks” in the worksheet. The PDF format looks good but doesn’t allow you to type into the blanks in the worksheet. The HTML format is crude but useful for quick for viewing online.

Do NOT open the Worksheet ODT files using any Microsoft products; they will mangle the format and mis-number the questions. Use the free Libre Office or Open Office programs to open these ODT documents. On campus, you can get a copy here: Course Introduction: Install Libre Office.

These first two worksheets require you to have read File System and Pathnames:

Worksheets prepare you for the upcoming assignments.

3.4 Upcoming testsIndexup to index

For full marks, read the Test Instructions (all the words) before your midterm tests.

Put these dates into your phone! Use the Algonquin Registered Name Game link to test your name before the test. I don’t answer questions about the instructions during the test.

  1. First Midterm test: 45 minutes; in your one-hour lecture class at 3pm on Wednesday in Week 5 (February 14).
  2. Second Midterm test: 45 minutes; in your one-hour lecture class at 3pm on Wednesday in Week 9 (March 21).

Tests take place in your one-hour lecture class, not in your lab period. You must write the test in the lecture class in which you are registered.

Each midterm test is 45 minutes long and contains approximately 45 multiple-choice questions similar to those found in Practice Tests and Answers.

3.4.1 Midterm Test #1 – Wednesday February 14 at 3pm in C346Indexup to index

  • Midterm #1 takes place Wednesday February 14 at 3pm in C346 in your scheduled lecture class (not in your lab period).
  • For full marks, you must read the Test Instructions before the test for important directions on how to enter your name, student number, answers, your lab (not lecture) section number, and the test version code on the question sheet and the mark-sense forms.
  • There may be more questions on the test than you can answer in the time allowed; answer the ones you know, first.
  • A set of practice questions and quizzes for the test are available in Practice Tests and Answers.

4 Notes from the ClassroomIndexup to index

4.1 Fifteen minute rule: don’t waste your timeIndexup to index

See the Course Introduction: Fifteen Minute Rule

4.2 Course Linux Server (CLS) account no loginIndexup to index

4.3 Locked out of the Course Linux ServerIndexup to index

As I said last week, if you typed your CLS userid or password incorrectly more than about three times, you got your IP address locked out. When you are locked out, follow the directions in Course Linux Server: Geting Locked Out for finding out your real IP address and getting it unblocked.

4.4 Assignment #1: Read All The WordsIndexup to index

4.5 Trying to use privileged commands sudo and su on the CLSIndexup to index

No, you are not allowed to use privileged commands such as sudo or su on my Course Linux Server. Use your own Linux virtual machine if you want to play with those commands.

4.6 Don’t use the place-holder userid abcd0001Indexup to index

5 Getting a job reference from your professorIndexup to index

Note from another former student:

I just wanted to thank you again for the reference that you me when
applying for a government position last year.
I ended up getting the job and I am part of a great team.
Thanks again,

If you want a good reference from me, get great marks and keep your lab class attendance up-to-date.

6 Copying from other students – plagiarismIndexup to index

Here is a note from a Student who was charged with plagiarism (academic fraud) in a previous year:

After everything, I would just like to thank you for not giving us
any harsher consequences. I really appreciate it, it's probably the
best Christmas gift after this stressful weekend I could get. And
what might be weird for you, I'd like to thank you for that you
found this plagiarism out because I have a lesson in my mind I will
never forget. I'm still very embarrassed [...] but these are the
consequences I have to face right now. Thank you once again and I
wish you Merry Christmas and Happy New Year.

One other student involved in the above case failed the course. Review the class notes on Plagiarism if you copy the work of other students or if you let your work be copied by other students. I know who you are and we’re going to have a chat about your behaviour soon.

7 Attacks on the CLSIndexup to index

Commands to show the number of locked out IP addresses and attempts to use locked-out IP addresses in /etc/hosts.evil:

$ wc /etc/hosts.evil
$ fgrep -c 'refused connect' /var/log/auth.log
$ fgrep 'refused connect' /var/log/auth.log | less

Count the unique locked-out addresses, and then show the top twenty:

$ fgrep 'refused connect' /var/log/auth.log | awk '{print $NF}' | sort -u | wc
$ fgrep 'refused connect' /var/log/auth.log | awk '{print $NF}' | sort | uniq -c | sort -nr | head -n 20

7.1 Bruce Schneier on cyber attacksIndexup to index


“For decades, hackers have used techniques such as jump hosts, VPNs, Tor and open relays to obscure their origin, and in many cases they work. I’m sure that many national intelligence agencies route their attacks through China, simply because everyone knows lots of attacks come from China.”

Take Notes in Class
| Ian! D. Allen, BA, MMath  -  idallen@idallen.ca  -  Ottawa, Ontario, Canada
| Home Page: http://idallen.com/   Contact Improv: http://contactimprov.ca/
| College professor (Free/Libre GNU+Linux) at: http://teaching.idallen.com/
| Defend digital freedom:  http://eff.org/  and have fun:  http://fools.ca/

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