Table of Contents

Part 3

Entries

Entry 1: November 2nd, 2012

client/server model designed to operate in a networked environment
- relationship of cooperating programs in an application
- server compnoent provides a function or service to one of many clients

Entry 2: November 7th, 2012

X X Window System X11 X11R6/X11R7

Learned about the LAIRwall 

Wall 01.offbyone.lan:0
Wall 02.offbyone.lan:0
Wall 03.offbyone.lan:0
Wall 04.offbyone.lan:0
Wall 05.offbyone.lan:0
Wall 06.offbyone.lan:0

Learned to xeyes on another computer (redirected xeyes to other screens) Also learned about oneko

Entry 3: November 9th, 2012

Learned about more commands : head, tail, paste, join, diff, patch, comm… We learned to filter data with the commands.

Head - outputs the first part of the file

  1. last | grep cgaines | head -3

Tail - output the last part of the files

  1. last | grep cgaines | tail -3

Entry 2: November 16th, 2012

Networking - communication amoung devices between a common medium using common protocols. 

  Standard - the way things should be done (English)
           - OSI module
  Protocol - set of rules (Northern Midland American English)
           - TCP/IP 
               - Application
               - Transport
               - Networking
                 - IP address (IPv4) 32-bit ~4.2 billion
                       - /sbin/ifconfig  10.80.2.38
                                 - 10 =
                                 - 80 = lair
                                 - 2  = subnet
                                 - 38 = unique node number
                       - show/manipulate routing, devices, policy routing and tunnels
                       - CCC ip 143.66.x.y (65,000 routable IPs)
               - Data Link

Keywords

unix Keyword 3

cron/crontab/at

Definition

      Is the time-based job scheduler in Unix-like computer operating systems. 
      Enables users to schedule jobs (commands or shell scripts) to run periodically
       at certain times or dates. 
      It is commonly used to automate system maintenance or administration.
      
      __Crontab_ (cron table) file, a configuration file that specifies shell 
      commands to run periodically on a given schedule.

References

  • Wikipedia
  • Sean Edwards
  • Harley Hahn's Guide to Unix and Linux

talk/ytalk Phase 2

Let's talk.

Definition

talk is a program that provides visual communication between two parties via text through the terminal. ( talk person ) Using this command alone will prompt the second party with the following message:

  • Message from TalkDaemon@his_machine…
  • talk: connection requested by your_name@your_machine.
  • talk: respond with: talk your_name@your_machine

At this point, the terminal will be now a chat window between the two parties. Both parties can type at the same time since their text appears in different parts of the window. To exit the window, use CTRL + C

ytalk is a program that provides visual communication between multiple parties via text through the terminal. It's basically the same program as talk, only it allows for multiple connections. ( ytalk [-s] [-Y] [-E] [-i] [-q] [-v] [-h hostname_or_ip] username… )

The username portion can be formatted in the following ways:

  • name - some user on your machine
  • name@host - some user on a different machine
  • name#tty - some user on a particular terminal
  • name#tty@host - some user on a particular tty on a different machine
  • name@host#tty - same as “name#tty@host”
  • aliasname - an alias defined in your .ytalkrc

You can also specify multiple usernames on the command line with ytalk ( ytalk george fred@hissun.edu marc@grumpy.cc )

Say hello to the options:

  • -s option starts your YTalk window in a shell.
  • -Y option requires a capital Y or N as an answer to any yes/no question.
  • -E option requires you to press escape once before answering a yes/no question (for people who type looking at the keyboard).
  • -i option disables the auto-invite port (meaning you won't see “talk to blah@blah.com”, but your talk daemon will beep you instead).
  • -q option causes YTalk to prompt you before quitting.
  • -v option prints the program version and exits.
  • -h option specifies the name or address of the local machine; this is useful on multi-homed machines, or virtual hosts, to specify which network interface to use for communication.

More to be added with more awesome details to come.

References

Demonstration

Demonstration of the indicated keyword. 

lab46:~$ cd src
lab46:~/src$ gcc -o hello hello.c
lab46:~/src$ ./hello
Hello, World!
lab46:~/src$

Experiment 3

Question

Will changing a relevant command in VI by a character completely change the outcome?

Resources

I just used techniques used in class to perform this experiment and then started manipulating the commands with no prior knowlegde of what the outcome would be.

Hypothesis

My Hypothesis is that by changing one character in the command will change the information

Experiment

I am going to type up some lines in VI and then I am going to input the command.

Using the command :%s/b/BB/g- this took all of the b's in the entire document and changed them to a BB.

Data

My name is BoBB and we had a BBaBBy its a BBoy, and charlie the unicorn and very funny. Billy BBoBB, is a hillBBilly, and a BBig one at that. Watching Hogan's Heroes and Hogan always seems to get the girls. BoBB we had a BBaB By its a very BBig BBoy.

Analysis

Based on the data collected:

Yes my hypothesis is correct, it shows that just changing one character out of the original command will change the result.

Conclusion

By doing this command I found out the many possibilities could happen when manupulating commands in VI.