CST8207 Week 04 Notes
I/O redirection, pipes, stdout, stderr, 2>&1, awk fields $1 $NF

Ian! D. Allen – www.idallen.com

Winter 2019 - January to April 2019 - Updated 2019-02-04 14:08 EST

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

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

  1. Week 04 Notes HTML – this file – Read All The Words
  2. Practice Tests and Answers – practice questions for your midterm test.
  3. Shell I/O Redirection – stdin, stdout, stderr, and Pipes
  4. Selecting Fields with awk – extracting fields from input lines and columns from input files using awk and $1 and $NF
  5. The VI (VIM) Text Editor – how to edit files. Don’t use nano!
  6. Next week: Shell Variables – quoting, local and environment variables, USER HOME SHELL PATH TERM $$
  7. List of Commands – Command names you should know, listed by week
  8. Video Tutorials on Lynda.com – tagged by week number
  9. Linux and Sysadmin News in the World – Linux skills earn $100,000 salaries.

1.2 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.

1.3 Lab work this weekIndexup to index

1.3.1 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 the web notes. (Please: Read All The Words)
  2. Do the relevant Worksheet(s).
  3. Do the relevant Assignment(s).

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.

Worksheets #02 and #03 require you to have read File System and Pathnames:

Worksheets #04 and #05 require you to have read Shell GLOB patterns and Shell I/O Redirection:

Worksheet #06 is for the optional VIM Bonus Assignment (extra credit):

Worksheets prepare you for the upcoming assignments.

1.4 Upcoming testsIndexup to index

Follow this link to see all your upcoming Quizzes and Tests. The dates are also posted on the Course Home Page and on Brightspace CST8207.

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

  1. First Midterm test: 45 minutes; in your one-hour lecture class in Week 6.
  2. Second Midterm test: 45 minutes; in your one-hour lecture class in Week 10.

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.

1.4.1 Practice Test #1 and Brightspace Quiz #2

Practice Tests and Answers – practice questions for your midterm test.

Quizzes and Tests – Quiz #2 is taken from Practice Test #1 and is good practice for your upcoming Midterm Test #1 in Week 6.

2 Notes from the ClassroomIndexup to index

2.1 Simplifying pathnamesIndexup to index

You will see lots of these: Rewrite each pathname as a simplified absolute pathname with no . or .. references:

  1. /home/me/../you/../../etc/../home/me/../you/../me/../foo
  2. /home/me/../you/../../etc/../home/me/../you/../me/../..
  3. /usr/./bin/../lib/../../etc/../usr/./lib/../bin/./bar
  4. /usr/./bin/../lib/../../etc/../usr/./lib/../bin/..
  5. /../../var/./a/../../var/b/../../etc/./bar/../foo
  6. /../../var/./a/../../var/b/../../etc/./bar/..

These questions and the answers are part of Practice Test #1 in Practice Tests and Answers. Look for questions starting with “Simplify this pathname”.

2.2 Draw file system diagramsIndexup to index

See last week’s note about drawing file system diagrams: Week 03 Notes HTML

2.3 Did not change password – CLS access revokedIndexup to index

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.

2.4 Commands UsedIndexup to index

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.
  • Bring your notes to class! Stop wasting time looking up commands.

3 TutoringIndexup to index

Many students find that hiring a personal tutor helps them get through the first term. Financial assistance is available. See the Tutoring heading in the Course Introduction.

3.1 Network Tutor Available on Saturday morningsIndexup to index

See your Networking course announcements.

4 SSH and HTTP Attacks on the CLSIndexup to index

You are not paranoid if they really are out to get you! See the Week 03 Notes HTML for command pipelines to count the ongoing attacks on the CLS.

5 Student Class RepresentativeIndexup to index

Andre D’Aoust was selected as your Class Representative for for 19W. Reach out to him with your concerns when they affect the entire class. Individual concerns are handled between the student and the professor.

6 Locked out of the CLSIndexup to index

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

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/
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