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

1. Week 05 Notes HTML – this file – Read All The Words
2. Unix Shell I/O Redirection (including Pipes)
3. Linux and Sysadmin News in the World
4. List of Commands You Should Know – keep a notebook!
5. Video Tutorials on Lynda.com – tagged by week number

• Create your lynda.com account and watch these sections of Unix for Mac OS X Users
  • 3. Working with Files and Directories
    • Unix text editors 6m 39s
      • vi/vim, nano
      • head, tail
    • Searching for files and directories 6m 32s
      • find using “wildcard” (GLOB) patterns - same as shell GLOB
  • 6. Directing Input and Output 20m 39s
    • Standard input and standard output 1m 24s
    • Directing output to a file 4m 13s
    • Appending to a file 2m 44s
    • Directing input from a file 5m 28s
    • Piping output to input 4m 40s
    • Suppressing output 2m 10s
  • 7. Configuring Your Working Environment 41m 28s
    • Setting command aliases 6m 59s
      • saving aliases in your .bashrc file

1.2 Assignments this weekIndex

Check the due date for each assignment and put a reminder in your agenda, calendar, and digital assistant.

• Read All The Words, Do, and then Submit via Blackboard:
  • Assignment #03 HTML – working with files: PS1, find, mkdir, mv, cp
  • Bonus (optional) Assignment #04 HTML – the VIM text editor
  • Assignment #05 HTML – using GLOB patterns and redirection
  • Really do Read All The Words. You don’t get a second chance to get it right.

1.3 Lab work this weekIndex

• Read The VI (VIM) Text Editor and optionally do the bonus Assignment #04 HTML.
• For Assignment 5 do Worksheet #04 PDF – shell GLOB patterns and Aliases
• Do Assignment #05 HTML – using GLOB patterns and redirection

1.4 Upcoming testsIndex

Read the Test Instructions (all the words) before your midterm tests.

1. First Midterm test: 45 minutes; in lecture class Friday in Week 5 (Oct 9)
2. Second Midterm test: 45 minutes; in lecture class Friday in Week 9 (Nov 6)

Tests take place in class in your one-hour lecture hour, not in your lab period.

3.1 Why take notes in class?Index

Take notes in class! A student writes:

But for the note taking, I personally find that without my laptop in front of me I am more focused on the teacher. Also with taking the notes by hand I find that the information that is presented to me in the lectures is remembered much easier.

But I do have my ipad in front of my with the class notes. This also helps me follow along with the examples that you present in class.

Also sometimes I read over the class notes after the class and fix my notes with anything that was missed.

• Do your lecture notes look like this?

• Does your Linux notebook look like this?

• Are you drawing file system trees (PDF)?

3.2 Read All The WordsIndex

• When I say “read all the words in a question, especially the Hints”
• When I say “don’t use Word to open the worksheets”
• When I say “do the worksheet to know how to do the assignment”
• When I say “keep a notebook with descriptions of each command”
• When I say “don’t work on a problem longer than 15 minutes before trying something else, such as getting help”

3.3 Missing lectures: save one hour to spend threeIndex

Students who save an hour by not attending a lecture usually end up spending three hours trying to answer assignment questions that I gave the answers to in the lecture. Work smarter.

3.4 Fifteen minute rule – REMINDERIndex

READ THIS: This is a repeat of what I told you back in Week 3:

Your time as a student is valuable. If you come up against a tough problem and make no progress in fifteen minutes despite your best efforts:

1. get help from a professor or lab instructor
2. get help from classmates
3. take a break
4. put it on hold and work on something else

This happens to all of us, and we need to watch out for it when it happens.

Be especially careful if you find yourself trying to solve a problem with online searches, since those searches will return answers irrelevant to the assignment. Read and search the course notes; don’t waste time searching the entire Internet.

3.5 Wasting your time with online searchesIndex

I watch students trying to solve assignment problems using online searches for answers. They may end up using commands we haven’t even covered yet:

Sorry, I dont know what sudo does; was getting help online to find files.

If you look at the List of Commands You Should Know that is given in the weekly readings every week, you will see that we never use the sudo command, so you should not be using it. Don’t use commands that you haven’t learned yet.

Also, you must never use any command that you don’t understand, even if you get it from the course notes or a worksheet. You risk deleting all your files if you use commands you don’t understand.

If you use online help, you will find thousands of complex wrong ways to do things. If you read the course notes, not Google, you will find a simple, right way.

You only need to use the commands we’ve learned so far in the course notes and the worksheets. That is all.

• Don’t use strange commands and/or options you find on the Internet. Stick with the commands in the web notes and assignments and listed in the weekly notes under List of Commands You Should Know.

3.6 Working Smart under LinuxIndex

Growing up under Mac/Windows, you are accustomed to having to “go to” a folder to make any changes to files in that folder. This leads to some inefficient behaviour under Unix/Linux, because Unix/Linux can operate on any file in any folder without having to “go” there:

The “Windows/Mac” way to create a file under a/b/c/d/date.txt:

$ mkdir a
$ cd a
$ mkdir b
$ cd b
$ mkdir c
$ cd c
$ mkdir d
$ cd d
$ date >date.txt
$ cd

The Unix/Linux way:

$ mkdir -p a/b/c/d
$ date >a/b/c/d/date.txt

The “Windows/Mac” way to rename a file under a/b/c/d/date.txt to be old.txt:

$ cd a
$ cd b
$ cd c
$ cd d
$ mv date.txt old.txt
$ cd

The Unix/Linux way:

$ mv a/b/c/d/date.txt a/b/c/d/old.txt

The “Windows/Mac” way to delete a/b/c/d/old.txt:

$ cd a
$ cd b
$ cd c
$ cd d
$ rm old.txt
$ cd

The Unix/Linux way:

$ rm a/b/c/d/old.txt

Using Unix/Linux pathnames, you can work faster, and all your commands are saved in your history for modification and re-use.

3.7 Useful Command to extract fields from lines: awkIndex

The oddly-named awk command can extract a field, by field number, from one or more input lines. See using awk to select fields.

3.8 Current Working Directory StackIndex

The shell built-in command pushd works like cd to change the current directory, but it saves the previous directory on a stack and lets you type popd to return to the previous directory. You may find this saves you some typing. See the shell man page or use the help built-in.

3.9 Attacks on the Course Linux ServerIndex

• Count the attacks: fgrep -c "refused connect" /var/log/auth.log
• Another way to count the lines (less efficient): fgrep "refused connect" /var/log/auth.log | wc
• Only show the last 10 lines: fgrep 'refused connect' /var/log/auth.log | tail
• See the current list of evil host IPs: less /etc/hosts.evil

Sep 30 12:33:50 Invalid user Patrick from 99.240.239.9
Sep 30 12:33:58 Failed password for invalid user Patrick from 99.240.239.9
Sep 30 12:34:35 Failed password for invalid user Patrick from 99.240.239.9
Sep 30 12:35:11 Failed password for invalid user Patrick from 99.240.239.9
Sep 30 12:35:14 Failed password for invalid user Patrick from 99.240.239.9
Sep 30 12:44:13 refused connect from cpec8be198f774b-cmbc140127c8b0.cpe.net.cable.rogers.com (99.240.239.9)

Oct  4 21:11:01 Failed password for pate0377 from 99.224.164.198
Oct  4 21:11:10 Failed password for pate0377 from 99.224.164.198
Oct  4 21:11:27 Failed password for pate0377 from 99.224.164.198
Oct  4 21:11:48 Invalid user pate0037 from 99.224.164.198
Oct  4 21:12:10 Failed password for invalid user pate0037 from 99.224.164.198
Oct  4 21:12:37 refused connect from cpe00fc8d22a843-cm00fc8d22a840.cpe.net.cable.rogers.com (99.224.164.198)

Oct  4 23:34:43 Invalid user martr0991 from 99.245.238.68
Oct  4 23:35:00 Failed password for invalid user martr0991 from 99.245.238.68
Oct  4 23:35:12 Failed password for invalid user martr0991 from 99.245.238.68
Oct  4 23:35:24 Failed password for invalid user martr0991 from 99.245.238.68
Oct  4 23:35:39 Failed password for invalid user martr0991 from 99.245.238.68
Oct  4 23:36:46 Invalid user mart091 from 99.245.238.68
Oct  4 23:36:57 Failed password for invalid user mart091 from 99.245.238.68
Oct  4 23:37:07 Failed password for invalid user mart091 from 99.245.238.68

Oct  4 20:27:51 Invalid user lavi2078 from 70.26.160.194
Oct  4 20:28:18 Failed password for invalid user lavi2078 from 70.26.160.194
Oct  4 20:28:29 Failed password for invalid user lavi2078 from 70.26.160.194
Oct  4 20:28:47 Failed password for invalid user lavi2078 from 70.26.160.194
Oct  4 23:43:39 Invalid user lavi2078 from 70.26.160.194
Oct  4 23:43:55 Failed password for invalid user lavi2078 from 70.26.160.194
Oct  4 23:45:09 refused connect from bas1-jockvale05-1176150210.dsl.bell.ca (70.26.160.194)

Oct  5 01:36:50 Invalid user  from 70.55.30.201
Oct  5 01:37:03 Failed password for invalid user  from 70.55.30.201
Oct  5 01:37:06 Failed password for invalid user  from 70.55.30.201
Oct  5 01:37:30 Failed password for invalid user  from 70.55.30.201
Oct  5 01:37:32 Failed password for invalid user  from 70.55.30.201
Oct  5 01:38:17 refused connect from bas2-kanata16-1178017481.dsl.bell.ca (70.55.30.201)

4.1 Lock-out is not an excuse for non-submissionIndex

A student writes me the night before the assignment is due:

I locked myself out of the CLS. I cant hand in my assignment because of this.

You can. As it says in the Course Linux Server notes, you can submit your assignment from any other IP address. If you’re locked out of home, go somewhere else to submit. You can always submit from school.

Working from home is a privilege. If you abuse the privilege and lock yourself out, go to school.