Updated: 2017-03-13 09:08 EDT

1 Readings, Assignments, Labs, Tests, and ToDo

1.1 Read (at least) these things (All The Words)

  1. Week 03 Notes HTML – this file – Read All The Words
  2. File System and Pathnames – ROOT, absolute, relative, dot, dot dot
  3. Directories: ROOT, /root, HOME, /home, and current
  4. Searching for and finding files by name, size, use, modify time, etc.
  5. Shell GLOB patterns (wildcard pathname matching)
  6. List of Commands You Should Know
  7. Linux and Sysadmin News in the World
  8. Video Tutorials on Lynda.com – tagged by week number

1.2 Assignments this week

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.

1.3 Lab work this week

1.4 Worksheets

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. Worksheet. 3. Assignment.

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 download Libre Office here.

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

Worksheets prepare you for the upcoming assignments.

2 Upcoming tests

For full marks, read the Test Instructions (all the words) before your midterm tests. Use the 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 lecture class 10am on Friday in Week 5 (Feb 10)
  2. Second Midterm test: 45 minutes; in lecture class 10am on Friday in Week 9 (Mar 17)

Tests take place at 10am in your 50-minute lecture class, not in your lab period. Each midterm test is 45 minutes long and contains approximately 45 multiple-choice questions.

2.1 Midterm Test #1 – February 10

3 Notes from the Classroom

An Update Is Available

An Update Is Available

Monday Pathnames Board1

Monday Pathnames Board2

3.1 Did not change password – CLS access revoked

Students will have their CLS accounts disabled if they have not changed their default password. (I do not want people breaking into my machine because of you.)

See my online timetable for how to make an office appointment to see me if you want your account back.

3.2 Fifteen minute rule: don’t waste your time

See the Course Introduction: fifteen minute rule

3.3 Drawing File System Diagrams

See the note in Assignment #03 HTML about drawing file system diagrams on paper. Do it!

File System Drawing 1

File System Drawing 2

3.4 Commands Used

Keep a notebook with a List of Commands in it.

  • You need to write down yourself what each command does.
  • Check the updated list of commands each week.
  • I will check for this list in your lab periods.

4 Attacks on the CLS

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' /var/log/auth.log
$ fgrep 'refused' /var/log/auth.log | less

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

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

Password failures:

$ fgrep -c 'Failed' /var/log/auth.log
$ fgrep 'Failed' /var/log/auth.log | less

Userid failures:

$ fgrep -c 'input_userauth' /var/log/auth.log
$ fgrep 'input_userauth' /var/log/auth.log | less

You can use the whois command on Linux to identify which country is responsible for an IP address, or use a Web Whois Lookup. (The Linux whois command is blocked from use at Algonquin College, except if you are on the CLS. You can’t use the Linux command in your own Linux machines on campus. Use it on the CLS or use the web interface instead.)

5 Locked out of the CLS

When you are locked out, follow the directions in the notes to get your IP address re-enabled.

Take Notes in Class

Take Notes in Class

Author: 
| 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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