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Part 1
Entries
Entry 1: February 9th, 2012
On the 9th of February we learned how to use arrays to take a user inputted word and break it into letter parts, store it in an array, and finally print it to the screen along with the letter ASCII values. This was of significance because we learned how to use an manipulate elements of an array with pointers and how to manipulate user input. We used the array word with pos for positioning and indexing parts of the word array for each letter, and to use those indexes of the word array to find things out about the letters. I did not find anything confusing when writing this program along with the instructor, but I have worked with arrays before.
Here is the source code of the program that was written in class on the 9th of February:
#include <stdio.h> #include <stdlib.h> int main(){ char *word, len = 0, x, pos = 0; word = (char *)malloc(sizeof(char)*24); fprintf(stdout, "Please enter a word: "); fscanf(stdin, "%s", word); x = *(word + pos); while ((x != '\0')&&(x != '\n')){ printf("In this while, x is %hhd\n", x); len++; pos++; x = *(word + pos); } for (pos = 0; pos < len; pos++){ fprintf(stdout, "%c", *(word + pos) - 32); } fprintf(stdout, "\n"); return(0); }
Entry 2: February 14th, 2012
On the 14th of February we learned how to use the main() function's inherited parameters to accept input in a different way than we are used to. This was of significance because it was a new way of accepting input in a more efficient way that is already included in the c language when we use the main() function. This is a very useful method of accepting arguments when the program is first run and a very efficient way of defining those arguments and having a pointer to point to them. I find that the main() function's parameters are confusing at first to work with and I have no documentation yet of the main() function, but I would assume it is part of the <stdio.h> file. There have yet to be too many challenges that I have not been able to overcome, due to the way the material is presented and the time given to play with the things we learn.
Here is the source code of the program that was written in class on the 14th of February:
#include <stdio.h> #include <stdlib.h> int main(int argc, char **argv){ unsigned char i; if (argc<2){ printf("%8s must be run with 1 or more arguments, you only provide %hhu\n", *(argv+0), (argc-1)); exit(1); } printf("You ran this program with a %hhu arguments, they are:\n", argc); for (i = 0; i < argc; i++){ printf("argv[%hhu]: %s\n", i, *(argv+i)); } return(0); }
Entry 3: February 16th, 2012
On the 16th of February we were made to write a program that associated everything we had done in class previously and outside of class to show that we could apply what we had learned so far. This was of significance because it was a way to not only test yourself but to show to the teacher that you could learn efficient through his methods, and through your own personal time devoted to the subject. If you were able to complete the task in the class period time available, it was a statement that said you understood everything taught so far in the class and were able to duplicate it and manipulate it all into one program. Some of the concepts that might not make perfect sense to me are mostly just pointers, but I feel as I find more uses for pointers, I will understand them more. I find that I am not facing too much of a challenge because I have experience with the subject matter through many different opportunities I have been given.
Here is the source code of the program that was written in class on the 16th of February:
#include <stdio.h> #include <stdlib.h> #include <stdbool.h> int main(int argc, char **argv){ int input; bool check = false; unsigned char i; while (check == false){ printf("Enter a value (0-4):"); scanf("%d", &input); if (input > 4 || input < 0){ printf("You have entered an incorrect value.\n"); check = false; }else{ for (i = 0; i < argc; i++){ printf("argv[%hhu][%hhu]: %c\n", i, input, *(*(argv+i)+input)); } check = true; } } return(0); }
Entry 4: February 16th, 2012
On the 16th of February I created virtual machines on the virtual machine server my group had created early in the HPC class. This was of significance because it will allow me to complete the network services project which comes next in my order of things and I plan on creating a proxy of some sort. Some of the problems that I ran into would include file modifications for xm##.cfg mirror links and problems with the xen conf file. I find that I am facing challenges every day in HPC and in turn learning a lot about cool projects that can be completed with the tools we learn each day through direct experience and really just diving right into things to learn about them, which is actually my favorite way of learning.
Here is the commands I had to run to complete the project:
root@vmserver02:~# xm create -c /xen/conf/vm31.cfg root@vmserver02:~# xm create /xen/conf/vm31.cfg lab46:~$ ssh root@vm31.student.lab
Keywords
cprog Keywords
cprog Keyword: Pointers
Definition
Pointers to me are used as a way of referencing something without calling it directly, and they are useful as I have seen because you can change the location a pointer points at depending on the situation and outcome you desire. You could even use an array of pointers to complete a task. I look at pointers as a reference or indirect direct way to change and manipulate something without using the thing that is being changed or manipulated.
Demonstration
To use pointers, there are a couple of things to consider:
- Address of: *value = &x (Pointing value (a pointer) to the address of the variable x)
- Dereferencing: *value (* denotes the dereference of a variable, making it a pointer) (This makes it container less)
- Assignment: You will notice below with a demonstration how to assign a pointer. (char *value; value = (char *)malloc(sizeof(char)*4);)
To demonstrate pointers, I will show a code block using pointers and its output.
#include <stdio.h> #include <stdlib.h> int main(){ char *value, i; value = (char *)malloc(sizeof(char)*4); *(value+0)=0; *(value+1)=1; fprintf(stdout, "Please enter a value (-128 - +127): "); fscanf(stdin, "%hhd", &i); *(value+2)=i; *(value+3)=(2*i)+3; for (i = 0; i <= 3; i++){ printf("%hhd\n", *(value+i)); } return(0); }
lab46:~$ gcc -o prog7 prog7.c lab46:~$ ./prog7 Please enter a value (-128 - +127): 8 0 1 8 19 lab46:~$
cprog Keyword: Selection Structures (if, case/switch)
Definition
Selection Structures are conditional statements that determine a path to take depending on the state of the condition. (True/False)
Demonstration
To demonstrate a Selection Structure, I will be using the If Selection Structure.
if (input > 4 || input < 0){ printf("You have entered an incorrect value.\n"); check = false; }else{ for (i = 0; i < argc; i++){ printf("argv[%hhu][%hhu]: %c\n", i, input, *(*(argv+i)+input)); }
cprog Keyword: Repetition/Iteration Structures (for, while, do while)
Definition
Repetition/Iteration Structures are a way of repeating certain contents of code until a condition is satisfied. They are usually defined mostly by whether a statement is True or False, and in the case of a while, as long as the statement is True, the while will continue to iterate.
Demonstration
As a demonstration, I will show a code example of a while loop and a for loop.
while (check == false){ printf("Enter a value (0-4):"); scanf("%d", &input); if (input > 4 || input < 0){ printf("You have entered an incorrect value.\n"); check = false; }else{ for (i = 0; i < argc; i++){ printf("argv[%hhu][%hhu]: %c\n", i, input, *(*(argv+i)+input)); } check = true; } }
cprog Keyword: Header Files (Local and System), C Standard Library (Libc), Libraries
Definition
Header Files are files that are applied to c code to incorporate libraries for use of their functions and data structures.
Demonstration
This demonstration will show a couple header files being included in a c code environment.
#include <stdio.h> #include <stdlib.h> #include <stdbool.h>
cprog Keyword: logic and operators (and, or, not, xor)
Definition
Logic and operators include devices for comparing and assigning variables. For example: int x = 0 (The '=' assigns the integer value of 0 to the integer variable x).
Demonstration
Demonstration for this keyword will include using AND (&&), OR (||), GREATER THAN (>), LESS THAN (<), and the Assignment Operator ( = ).
if (input > 4 || input < 0){ check = false; } if (input > 4 && input < 0){ check = true; }
cprog Keyword: Arrays (standard notation, pointer arithmetic, single-dimensional, multi-dimensional)
Definition
Arrays can be thought of as containers with indexes to each element in their ordered container. The ability to store data separately within a container and be able to access it easily with an index is the reason why Arrays are so useful. Arrays to me are dynamic storage containers with easily accessed schemes of data.
Demonstration
In this demonstration, I will be showing in c code some different Array types.
int argc; //Array of integers char **argv; //Array of character pointers int x[2]; //Array of integers with a size of 2 int t[2][2]; //Multidimensional Array with a Row size of 2 and Column size of 2
cprog Keyword: Standard I/O (STDIO, STDOUT, STDERR)
Definition
Standard I/O is a library of input, output, and error message types to be prompted to the terminal screen. Standard I/O must be included in a programming file such as .c for its input, output, and error message functions to work.
Demonstration
What follows is a demonstration of including Standard I/O to a .c file and using some of its functions to perform prompting tasks.
#include <stdio.h> fprintf(stdout, "Please enter a value (-128 - +127): "); fscanf(stdin, "%hhd", &i);
cprog Keyword: Functions
Definition
Functions as used by me are a set of instructions that can be defined by a name and referenced by the main part of a program to complete some sort of sub task to a greater full task.
Demonstration
Here is an example of functions in the language c:
1 #include <stdio.h> 2 3 int sum(int, int, int, int); 4 float average(int, int, int, int); 5 6 int main(){ 7 int a, b, c, d, high, low; 8 a = b = c = d = 0; 9 printf("Enter first value: "); 10 fscanf(stdin, "%d", &a); 11 printf("Enter second value: "); 12 fscanf(stdin, "%d", &b); 13 if (a > b){ 14 high = a; 15 low = b; 16 }else{ 17 low = a; 18 high = b; 19 } 20 printf("Enter third value: "); 21 fscanf(stdin, "%d", &c); 22 if (c > high){ 23 high = c; 24 }else{ 25 if (c < low){ 26 low = c; 27 } 28 } 29 printf("Enter fourth value: "); 30 fscanf(stdin, "%d", &d); 31 if (d > high){ 32 high = d; 33 }else{ 34 if (d < low){ 35 low = d; 36 } 37 } 38 fprintf(stdout, "The sum of %d, %d, %d, and %d is: %d\n", a, b, c, d, sum(a, b, c, d)); 39 fprintf(stdout, "The average of %d, %d, %d, and %d is: %f\n", a, b, c, d, average(a, b, c, d)); 40 fprintf(stdout, "The highest input is: %d\n", high); 41 fprintf(stdout, "The lowest input is: %d\n", low); 42 return(0); 43 } 44 45 int sum(int n1, int n2, int n3, int n4){ 46 return(n1 + n2 + n3 + n4); 47 } 48 49 float average(int n1, int n2, int n3, int n4){ 50 return((float)(n1 + n2 + n3 + n4)/4); 51 }
cprog Objective
cprog Objective
Write and compile code that utilizes programming constructs.
Definition
This objective entails the use of nano or vi along with the use of gcc to write and compile code within a certain standard of syntax and purpose.
Method
The method to which I will use to measure my success in this objective is to show the steps and examples of how I have already completed this objective.
Measurement
Steps to completing this objective include:
1. The use of nano or vi to edit text and create a .c file type.
lab46:~$ nano test.c
lab46:~$ vim test.c
#include <stdio.h> int main() { printf("Testing a printf."); return(0); }
2. The use of gcc to compile code and check the syntax of the code.
lab46:~$ gcc -o test test.c lab46:~$
3. Testing the code by running the file that I have compiled the .c file to.
lab46:~$ ./test Testing a printf. lab46:~$
Analysis
Reflections:
- I believe I have done well and have shown success in this objective.
- I believe the room for improvement lays in the matter of programming constructs.
- I believe the measurement could be more effective with code examples as I have used above.
- I do have the belief that this would be an effective and simple employment.
- I do not believe the course objective should be altered in any way.
hpc0 Keywords
hpc0 Keyword "Screen"
Definition
Screen to me, in unix, is an orgasmic experience of endless possibilities. It is the very meaning of multitasking efficiently and its uses are endlessly approaching greatness, like the graph of 1/x, it never reaches fully to 0, but it will always be getting closer and closer to perfect value and significance. Putting all my admiration aside, screen is used to create a session of many windows within a terminal window. Well, you ask, why is it called “Screen” if it creates a plural cornucopia of windows of great potential. Well, don't be a dummy, keep it simple stupid, think of it as a frame or structural base that you build upon and a very sturdy one if you ask me. So, if you find yourself wanting to multitask your butt off, or you just really want to show off to all your friends, you should get to know your new best friend, “Screen”.
Demonstration
Demonstration of the chosen keyword.
So, are you finally ready to be the future, be the unstoppable, well, you'll be more efficient at the least. Then follow me on this great journey and you shall find the greatness in all things that are “Screen”. Fine, I get it, you are tired of me talking so much. Without further ado I shall now show you the awesome-sauce that is “Screen”…
*Awesome Eye of the Tiger Music comes on in the background*
lab46:~$ screen
Make sure to say “y” or “yes” when installing/setting up screen.
lab46:~$ screen -ls There is a screen on: 13985.pts-50.lab46 (02/14/2012 12:17:40 PM) (Attached) 1 Socket in /var/run/screen/S-jpettie.
hpc0 Keyword: Screen Cont.
Definition
Dude, you totally made the right choice in choosing to continue your knowledge of the Screen universe with me. So, lets get to it, right!?
..Right.
There are things you just must know about screen to really make it shine and once you realize what you are doing, you will be amazed.
Disclaimer: If you are one of those guys who are like, I ain't ever amazed bro, sit back and watch the magic yo, and I ain't yo bro dude.
In this section of the continuum of Screen, we will discuss some useful keystrokes to manipulate Screen to your needs, or is it Screen that is manipulating you? That is the question indeed. What better way to do such a thing than with Hotkeys, lets kick it old school yo.
Hotkeys
Attach to a screen session:
lab46:~$ screen -r
Control Command Hot-key Combinations for Reference (Simple):
- Control + c: Create new window.
- Control + a + a: Swap between windows.
- Control + “: Show all windows running.
- Control + a + A: Name current window.
- Control + a + k: Destroy current window.
- Control + a + n: Change to next window.
- Control + a + p: Go back a window.
- Control + a + \: Destroy all windows.
- Control + a + D: Detach from running Screen.
Disclaimer: If you don't believe me, jerk…, anyway, use:
- Control + a + ?: Shows list of all commands.
hpc0 Keyword: Screen Split
Definition
So now you understand how to create windows, name windows, swap between windows, even how to kill windows, and you ask, is that it? Maybe you'd even say I guess that is alright, its kinda cool. Well, there is more to this story than you might realize at first sir. Get ready to have your mind blown and your efficiency level skyrocket to over 9000!!!!!!
The story began back when someone decided that should open two terminals because they want to work on two different windows at the same time, and maybe they used win 7 to snap it to either side of their screen, well, I am here to save you from opening too many screens and endless terminals to multitask. It can be done in Screen, and it is time you learn how to do it.
Demonstration
The commands you'll want to know to split your screen into vertical and horizontal windows as many times as you'd like are as follows:
- Control + a + S: Split screen into n windows horizontally (where n is how many times you do such a thing, feel free to do this a lot, its fun, trust me.).
- Control + a + | (Don't get this confused with the letter 'l' or the letter 'i', it is a pipe, or rather a shift '\'): Split screen into n windows vertically
- Control + a + TAB: Swap focus between the split windows in screen. (Multitask be yours, like magicks yo)
- Control + a + X: Destroy a window.
And so you can see the magic that will happen, here is an example of what you can expect to create:
words? jpettie@lab46:~/src$ cd unix 21:35 < Jacob> thats exactly what I was going for, how did you know? jpettie@lab46:~/src/unix$ ls 21:36 < wedge> no, the ultimate aim is for it to be readable and informative, and especially to the cs1.txt lab0.txt lab1.txt original author months down the road jpettie@lab46:~/src/unix$ ls 21:36 < wedge> but, seeing as it is publicly accessible, just know that the intarwebz can also read it cs1.txt lab0.txt lab1.txt 21:39 < Jacob> well, I just wanted to use awesome-sauce jpettie@lab46:~/src/unix$ ls -all 21:39 < wedge> feel free total 12 21:39 < wedge> I think it makes it more enjoyable drwxr-xr-x 3 jpettie lab46 61 Jan 28 18:57 . 21:40 < Jacob> as long as you enjoy it, I should be doing well drwx------ 6 jpettie lab46 68 Jan 28 18:40 .. 21:41 < wedge> to enjoy and be informed drwxr-xr-x 6 jpettie lab46 92 Jan 31 16:52 .svn 21:41 < Jacob> gonna hit the world with matrix level stuff, when I hit splits -rw-r--r-- 1 jpettie lab46 705 Jan 28 18:57 cs1.txt 21:41 < wedge> knock knock neo -rw-r--r-- 1 jpettie lab46 2489 Jan 25 14:38 lab0.txt 21:43 < wedge> anywho... I'm going to wander... any last requests? -rw-r--r-- 1 jpettie lab46 3327 Jan 28 18:56 lab1.txt 21:43 < Jacob> knock knock , endless screen possibilities jpettie@lab46:~/src/unix$ 21:43 < Jacob> um, don't check it until tomorrow at 1? jpettie@lab46:~/src/unix$ 21:43 < Jacob> hahah 21:44 < wedge> 0100 hours? 21:44 < wedge> :) 21:44 < Jacob> just joking 21:44 < Jacob> I'll have a lot done by midnight 21:44 < Jacob> most likely all of it 21:44 < wedge> I'll likely not be looking at it until tomorrow afternoon at the earliest 21:45 < wedge> good night all 21:46 < Jacob> I be good student from now on 21:46 < Jacob> ;p 21:46 < Jacob> good night 21:57 < rmatsch> hey 21:58 < rmatsch> cat utility not working 22:26 < Jacob> how are you using it? [22:27] [Jacob(+i)] [4:irc/#unix(+Pnt)] [#unix] 0 irc 4 bash GNU nano 2.2.4 File: icprog.c Sending on Socket/fallback DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3 #include <stdio.h> DHCPOFFER from 10.80.3.62 #include <stdlib.h> DHCPREQUEST on eth0 to 255.255.255.255 port 67 #include <stdbool.h> DHCPACK from 10.80.3.62 bound to 10.80.3.31 -- renewal in 19118 seconds. int main(int argc, char **argv){ done. int input; INIT: Entering runlevel: 2 bool check = false; Starting enhanced syslogd: rsyslogd. unsigned char i; Starting OpenBSD Secure Shell server: sshd[ 11.401708] NET: Registered protocol family 10 while (check == false){ [ 11.402227] lo: Disabled Privacy Extensions printf("Enter a value (0-4):"); . scanf("%d", &input); Starting periodic command scheduler: crond. if (input > 4 || input < 0){ printf("You have entered an incorrect value.\n"); Debian GNU/Linux 5.0 vm31 hvc0 check = false; }else{ vm31 login: vmserver02:~# ssh root@vm31.student.lab for (i = 0; i < argc; i++){ The authenticity of host 'vm31.student.lab (10.80.3.31)' can't be established. printf("argv[%hhu][%hhu]: %c\n", i, input, *(*(argv+i)+input)); RSA key fingerprint is 39:41:a6:f0:21:67:ac:fc:3b:b6:55:8f:1d:2f:be:c6. } Are you sure you want to continue connecting (yes/no)? y check = true; Please type 'yes' or 'no': yes } Warning: Permanently added 'vm31.student.lab,10.80.3.31' (RSA) to the list of known hosts. } root@vm31.student.lab's password: return(0); Linux vm31 2.6.26-2-xen-686 #1 SMP Wed Sep 21 09:56:47 UTC 2011 i686 } The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent ^G Get Help ^O WriteOut ^R Read File ^Y Prev Page ^K Cut Text ^C Cur Pos permitted by applicable law. ^X Exit ^J Justify ^W Where Is ^V Next Page ^U UnCut Text ^T To Spell vm31:~# 2 bash 6 bash
hpc0 Keyword: Virtualization
Definition
Virtualization is a way to create something that does not rely directly on the constraints of hardware.
Demonstration
A demonstration of this would be creating virtual machines on a virtual machine server which I have already implemented, but the way to create the virtual machines is as follows:
root@vmserver##:~# xm create -c /xen/conf/vm##.cfg root@vmserver##:~# xm create /xen/conf/vm##.cfg
hpc0 Keyword: Configuration
Definition
Configuration has come to me in the meaning of changing the way something runs or starts up, depending on a file that is referenced by the service that uses it.
Demonstration
A demonstration of this would be for pvpgn, when I had to edit the .conf files of different services that make a whole of a server for the service of a pvpgn server to work correctly.
hpc0 Keyword: Backups
Definition
In our field, Backups are a very useful technique to create a restore point for a program or database and many other sorts of project files or directories before a big change or developmental process.
Demonstration
A demonstration of this is found at my work on a daily basis where we automate the backup of our mysql database so that if anything were to happen to it, we would be able to implement a restore to precious data.
hpc0 Keyword: Installation
Definition
Installation in my words would be the creation of a working copy of a program onto your computer from a downloaded source found online.
Demonstration
An example of this would be using Aptitude to install mysql.
vm31:~$ aptitude install mysql
hpc0 Keyword: Documentation
Definition
Documentation to me is a read me file or even a forget me file, pun intended. It is the bread and butter of working on someone else's code if they have comments inside their code explaining something about each part or how to run the program correctly.
Demonstration
Here is an example of documenting with comments in c code.
//This is an example comment line /* This is an example of a multiple line comment Heres some more info and finally */
hpc0 Objective
hpc0 Objective
Demonstrate problem solving capabilities.
Definition
I believe what this objective can be defined as is a process that has been honed in on by the practice of completing projects of different levels of difficulty and expected outcomes.
Method
To show I have accomplished this objective, my method will include an example of a project where I have applied the practice of problem solving.
Measurement
Here is an example of a project I have completed by solving problems recently. The problems I encountered included bad mirror links in the cfg file of the xm virtual machine I was trying to create along with changes to the xm conf files before executing the creation of the virtual machine.
root@vmserver02:~# xm create -c /xen/conf/vm31.cfg root@vmserver02:~# xm create /xen/conf/vm31.cfg lab46:~$ ssh root@vm31.student.lab
Analysis
I believe I did well in performing this task and showing that I could solve the problems that I encountered along the way in completing the project. I definitely think that there is room for improvement in all things we do, but especially in problem solving. I have a philosophy that you have to experience a problem, or make a mistake to truly learn how to correct it and not repeat it in the future. I believe if I used a different project as an example with more detail going into how I approached and fixed the problems I came across, the measurement would be a more effective tool to show my skills. I believe it would be an efficient change to employ and I intend to do so in future opus Objective documentations. The course objective pretty much covers all it means to cover and should not be altered in any way, it is what it says, and problem solving is something people have to do every day in their lives no matter the field or task at hand.
unix Keywords
unix Keyword: The VI Editor
Definition
The VI Editor, one of the greats, nano on steroids. VI Editor is a text editor with much more to bring to the table, between its tools and its unique style of dealing with the editing of text. It is in simple a text editor with extras.
Demonstration
To demonstrate the VI Editor, I will show a fully functional VI Interface with the extra of line numbers and syntax highlighting:
lab46:~$ install vim lab46:~$ vi test.c
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <stdbool.h> 4 5 int main(int argc, char **argv){ 6 int input; 7 bool check = false; 8 unsigned char i; 9 while (check == false){ 10 printf("Enter a value (0-4):"); 11 scanf("%d", &input); 12 if (input > 4 || input < 0){ 13 printf("You have entered an incorrect value.\n"); 14 check = false; 15 }else{ 16 for (i = 0; i < argc; i++){ 17 printf("argv[%hhu][%hhu]: %c\n", i, input, *(*(argv+i)+input)); 18 } 19 check = true; 20 } 21 } 22 return(0); 23 } 24
unix Keyword: Local host
Definition
Local host is the computer you are working on, it is the web address of the computer you are working on, it is a loopback in networking. Although local host can take many forms, it is simply your computer's identifier.
Demonstration
If you were to type: http://localhost into your web browser, you would be returned with the local web service of your computer.
unix Keyword: Remote host
Definition
Remote hosts are computers that are not locally accessed, rather are at a distance from where you are. They are still accessible and you can retrieve data from them, but they are a distance away.
Demonstration
Remote hosts are usually thought of as network servers or just servers in general, where you would ssh into. An example of this to me would be:
lab46:~$ ssh root@vm31.student.lab
unix Keyword: Home directory
Definition
The way I believe a home directory works, is that it can be a supply source for many users, who can separately have their own subsystems of directories but all refer back to a starting point. Even though it can be used by many, each is very different in its own right, different files and directories based on the user.
Demonstration
This demonstration will show a Home directory with many users.
lab46:~$ cd /home lab46:/home$ ls ab000126 bdevaul cmcavoy drobie2 haas jhall40 jvanott1 lmcconn4 nrounds rrichar8 tdoud abranne1 bewanyk cmille37 ds000461 hansolo jhammo13 jwalrat2 lmerril3 nsano rsantia4 tedmist1 abrunda1 bfarr2 cmulkeri ds003420 hclark9 jj001572 jwhitak3 mallis3 nsr1 rshaw8 tfitch1 acanfie1 bh011695 cnicho13 dschoeff hepingerjj jjansen4 jwilli30 mbeschle nvergaso rthatch2 tgalpin2 acarpen5 bherrin2 comeaubk dshadeck hhabelt jjohns43 jwilso39 mbonacke nwebb ryoung12 thakes3 acrocker bhuffner cpainter dsherbur hps1 jjohnst8 jwood36 mbrigham oppenheim sblake3 thatcher adexter bkenne11 critten1 dshreve hramsey jkingsle jzimmer5 mbw6 pclose sc000826 tjohns22 adilaur1 bkrishe3 csit2310 dstorm3 hshaikh jkremer1 kamakazi mcantin3 pcremidi sclayton tkane1 aettenb3 bnichol7 csleve dtalvi hwarren1 jlantz4 kbell1 mclark35 pdowd sedward9 tkiser afassett bobpauljr cspenc12 dtaylo15 ian jlazaar kboe mcooper6 plindsa1 sjankows tl009536 agardin4 bort csteve16 dtennent imaye jluedema kc017344 mdecker3 pm004968 sjelliso tmizerak ahazen bowlett1 cwagner1 dtravis4 jandrew9 jm010967 kcard2 mdittler pmcconn1 skinney1 tmong ajernig2 brian cwilder1 dwalrat1 javery9 jmanley3 kcaton mearley1 qclark smacombe tp001498 ajoensen brobbin4 cwoolhis dwells6 jbaez jmille59 kcook6 mfailing radams4 smalik2 triley2 alius bstoll darduini dwrigh18 jbamper jmitch22 kcornel6 mfaucet2 rberry3 smatusic ts004985 amorich1 btaber2 dates eberdani jbarne13 jmunson kdenson mgough rbuchan7 smclaug3 vcordes1 anarde bwheat db010905 efarley jbesecke jmyers7 kgarrah1 mguthri2 rcaccia1 smd15 wag2 anorthr3 bwilso23 dchilso3 egarner jblaha jo009612 kgaylord mhenry9 redsting3d smilfor3 wedge anowaczy bwilson3 dcicora1 egleason jblanch1 jpettie kinney mkellogg reedkl spetka wezlbot ap016986 cacquah ddragoo emorris4 jbrant jphill17 kkrauss1 mkelsey1 rfinney2 spline wfischba appelthp cas21 dfoulk1 en007636 jbrizzee jr018429 klynch3 mmatt rglover squires wknowle1 aradka caustin8 dgirard3 erava jburlin1 jrampul1 kpryslop mowens3 rhender3 squirrel wroos aromero ccaccia dh002925 erebus jc006215 jsabin1 kreed11 mp018526 rhensen srk3 ystebbin as012495 ccarpe10 dh018304 eryan3 jcardina jschira1 kscorza mpage9 rj005436 srog zlittle ascolaro cchandan dherman3 estead jcavalu3 jshare1 ksisti2 mpaul6 rjohns41 ssmith85 zmccann asmedley ccranda2 dlalond1 eveilleu jcosgro4 jshort6 kwalker2 mpresto4 rkapela sswimle1 zward asowers cderick dm005264 ewester1 jdavis34 jsmit176 lburzyns mshort3 rlott strego astrupp cdewert dmagee3 ezajicek jdawson2 jstrong4 lcrowley mtaft4 rm002127 svrabel atoby cforman dmay5 fclark1 jdrew jsulli34 ld010818 mwagner3 rmatsch swarren4 atownsle cgoodwin dmckinn2 gc007950 jeisele jsulliv3 leckley mwarne11 rmoses sweller5 atreat2 ckelce dmurph14 gcalkin3 jellis15 jt011443 lgottsha mwitter3 rnewman swilli31 awalke18 ckuehner dpadget8 ggamarra jferrito jtongue2 lh000592 nandre rosenbll syang bblack1 clawren2 dparson3 gr015546 jfrail jtreacy lhubbar3 nbaird rpage3 synack bboaz cmace1 dpotter8 groush1 jfurter2 jtripp llaughl3 nblancha rpetzke1 ta018998 bbrown17 cmahler dprutsm2 gsnyder jh001093 jv001406 lleber ngraham2 rraplee tcolli12 lab46:/home$
unix Keyword: Current working directory
Definition
A current working directory to me is a folder a person has created and uses for files depending on the purpose of the folder and can access with cd issued commands and can change permissions on files inside of the folder.
Demonstration
Here is a current working directory of my own:
lab46:~$ cd src/cprog lab46:~/src/cprog$ ls bigNum cipher.c file ftypes functions.c icprog linkedlist.h out.txt prog1x5.c prog4 prog5 prog6.c prog8 prog9 test.c var2 bigNum.c cipher.txt file.c ftypes.c hint1 icprog.c message.in plain.txt prog3 prog4.c prog5.c prog7 prog8.c prog9.c var1 var2.c cipher decipher.txt file.txt functions hint1.c key.txt nofile.txt prog1x5 prog3.c prog4.c.save prog6 prog7.c prog8.c.save test var1.c lab46:~/src/cprog$ ls -l total 268 -rwxr-xr-x 1 jpettie lab46 9521 Mar 1 21:05 bigNum -rw-r--r-- 1 jpettie lab46 1832 Mar 1 21:05 bigNum.c -rwxr-xr-x 1 jpettie lab46 9452 Feb 28 14:20 cipher -rw-r--r-- 1 jpettie lab46 2323 Mar 1 19:55 cipher.c -rw-r--r-- 1 jpettie lab46 34 Feb 24 20:04 cipher.txt -rw-r--r-- 1 jpettie lab46 34 Feb 28 17:44 decipher.txt -rwxr-xr-x 1 jpettie lab46 7481 Feb 7 16:48 file -rw-r--r-- 1 jpettie lab46 372 Feb 7 16:48 file.c -rw-r--r-- 1 jpettie lab46 15 Feb 7 16:45 file.txt -rwxr-xr-x 1 jpettie lab46 8275 Mar 1 15:18 ftypes -rw-r--r-- 1 jpettie lab46 1007 Mar 1 16:10 ftypes.c -rwxr-xr-x 1 jpettie lab46 8058 Feb 24 15:09 functions -rw-r--r-- 1 jpettie lab46 1061 Feb 24 11:55 functions.c -rwxr-xr-x 1 jpettie lab46 7754 Feb 27 11:58 hint1 -rw-r--r-- 1 jpettie lab46 692 Feb 28 10:43 hint1.c -rwxr-xr-x 1 jpettie lab46 7136 Feb 16 16:14 icprog -rw-r--r-- 1 jpettie lab46 481 Feb 16 16:30 icprog.c -rw-r--r-- 1 jpettie lab46 19 Feb 24 21:48 key.txt -rw-r--r-- 1 jpettie lab46 509 Mar 1 21:01 linkedlist.h -rw-r--r-- 1 jpettie lab46 42 Feb 27 09:57 message.in -rw-r--r-- 1 jpettie lab46 0 Mar 1 23:42 nofile.txt -rw-r--r-- 1 jpettie lab46 14 Feb 7 16:48 out.txt -rw-r--r-- 1 jpettie lab46 0 Mar 1 23:42 plain.txt -rwxr-xr-x 1 jpettie lab46 11673 Mar 1 23:42 prog1x5 -rw-r--r-- 1 jpettie lab46 1165 Mar 1 23:42 prog1x5.c -rwxr-xr-x 1 jpettie lab46 6771 Jan 31 15:07 prog3 -rw-r--r-- 1 jpettie lab46 267 Jan 31 15:07 prog3.c -rwxr-xr-x 1 jpettie lab46 7031 Jan 31 16:02 prog4 -rw-r--r-- 1 jpettie lab46 452 Jan 31 16:02 prog4.c -rw-r--r-- 1 jpettie lab46 300 Feb 14 12:17 prog4.c.save -rwxr-xr-x 1 jpettie lab46 7039 Jan 31 16:36 prog5 -rw-r--r-- 1 jpettie lab46 246 Feb 2 11:07 prog5.c -rwxr-xr-x 1 jpettie lab46 7738 Feb 2 15:42 prog6 -rw-r--r-- 1 jpettie lab46 589 Feb 16 16:58 prog6.c -rwxr-xr-x 1 jpettie lab46 7453 Feb 7 16:24 prog7 -rw-r--r-- 1 jpettie lab46 338 Feb 7 16:24 prog7.c -rwxr-xr-x 1 jpettie lab46 7632 Feb 14 14:31 prog8 -rw-r--r-- 1 jpettie lab46 458 Feb 28 10:56 prog8.c -rw-r--r-- 1 jpettie lab46 459 Feb 14 12:17 prog8.c.save -rwxr-xr-x 1 jpettie lab46 6965 Feb 14 15:40 prog9 -rw-r--r-- 1 jpettie lab46 384 Feb 28 11:06 prog9.c -rwxr-xr-x 1 jpettie lab46 7465 Feb 24 21:46 test -rw-r--r-- 1 jpettie lab46 484 Feb 24 21:46 test.c -rwxr-xr-x 1 jpettie lab46 6786 Jan 26 15:49 var1 -rw-r--r-- 1 jpettie lab46 305 Jan 26 15:49 var1.c -rwxr-xr-x 1 jpettie lab46 6794 Jan 26 16:41 var2 -rw-r--r-- 1 jpettie lab46 256 Jan 26 16:41 var2.c lab46:~/src/cprog$
unix Keyword: Text Processing
Definition
The way I think of Text Processing is a technique or device used to edit, and save text into files or from files but can also be used just on plain text as well to change it (for example: to change the color of text).
Demonstration
A tool used to process text I've used in the past and would be a good demonstration would be “nano”
lab46:~/src/cprog$ nano prog3.c
#include <stdio.h> int main(){ int v = 17; int *p1 = NULL; printf("v is %u \n", v); p1 = &v; printf("*p1 is %u\n", *p1); *p1 = 53; printf("v is %u\n", v); printf("*p1 is %u\n", *p1); v = 7; printf("v is %u\n", v); printf("p1 is %u\n", *p1); return(0); }
unix Keyword: Job Control
Definition
To me, Job Control is just another way of saying multitasking, but to multitask efficiently. To control the outcome and resources needed by each job to complete its task and to give the right results along with being able to run them both at the same time.
Demonstration
An example of Job Control to me, is using more than one windows in a screen session and having one be a tail to log files, and the other to run a bnetd file for a pvpgn server.
tail: invalid option -- * jpettie@lab46:~$ ssh root@vm31.student.lab Try `tail --help' for more information. Warning: Permanently added 'vm31.student.lab,10.80.3.31' (RSA) to the list of known hosts. vm31:/usr/local/var# tail --help root@vm31.student.lab's password: Usage: tail [OPTION]... [FILE]... Linux vm31 2.6.26-2-xen-686 #1 SMP Wed Sep 21 09:56:47 UTC 2011 i686 Print the last 10 lines of each FILE to standard output. With more than one FILE, precede each with a header giving the file name. The programs included with the Debian GNU/Linux system are free software; With no FILE, or when FILE is -, read standard input. the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Mandatory arguments to long options are mandatory for short options too. --retry keep trying to open a file even if it is Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent inaccessible when tail starts or if it becomes permitted by applicable law. inaccessible later; useful when following by name, Last login: Sat Mar 3 02:57:33 2012 from lab46.offbyone.lan i.e., with --follow=name vm31:~# cd /usr/local -c, --bytes=N output the last N bytes; alternatively, use +N to vm31:/usr/local# cd sbin output bytes starting with the Nth of each file vm31:/usr/local/sbin# ls -f, --follow[={name|descriptor}] bnetd bntrackd d2cs d2dbs output appended data as the file grows; vm31:/usr/local/sbin# -f, --follow, and --follow=descriptor are equivalent -F same as --follow=name --retry -n, --lines=N output the last N lines, instead of the last 10; or use +N to output lines starting with the Nth --max-unchanged-stats=N with --follow=name, reopen a FILE which has not changed size after N (default 5) iterations to see if it has been unlinked or renamed (this is the usual case of rotated log files) --pid=PID with -f, terminate after process ID, PID dies -q, --quiet, --silent never output headers giving file names -s, --sleep-interval=S with -f, sleep for approximately S seconds (default 1.0) between iterations. -v, --verbose always output headers giving file names --help display this help and exit --version output version information and exit If the first character of N (the number of bytes or lines) is a `+', print beginning with the Nth item from the start of each file, otherwise, print the last N items in the file. N may have a multiplier suffix: b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024, GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y. With --follow (-f), tail defaults to following the file descriptor, which means that even if a tail'ed file is renamed, tail will continue to track its end. This default behavior is not desirable when you really want to track the actual name of the file, not the file descriptor (e.g., log rotation). Use --follow=name in that case. That causes tail to track the named file by reopening it periodically to see if it has been removed and recreated by some other program. Report bugs to <bug-coreutils@gnu.org>. vm31:/usr/local/var# tail -f .log tail: cannot open `.log' for reading: No such file or directory tail: no files remaining vm31:/usr/local/var# tail -f *.log Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Emperor-2" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Red Alert 2-1" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Red Alert 2-2" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Nox Quest-1" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Yuri's Revenge-1" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Yuri's Revenge-2" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Lob 38 0" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Lob 39 0" Mar 01 23:43:34 [info ] channel_destroy: destroying channel "Lob 40 0" Mar 01 23:43:34 [info ] main: server has shut down
unix Keyword: Regular Expressions
Definition
When I think of Regular Expressions, I tend to think of if statements, comparing two things and seeing if they match, depending on type of course.
Demonstration
Here is a while statement to show Regular Expressions:
while (check == false){ some sort of code to execute here }
unix Objective
unix Objective
Exposure to command-line tools and utilities
Definition
In my own thoughts, I would consider the completion of this objective as using tools such as vi to accomplish a task, or even produce a program in c.
Method
The method I will use to show the completion of this objective is an example of vi editing of a program.
Measurement
Here is an example of vi after adding line numbers and syntax highlighting:
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <stdbool.h> 4 5 int main(int argc, char **argv){ 6 int input; 7 bool check = false; 8 unsigned char i; 9 while (check == false){ 10 printf("Enter a value (0-4):"); 11 scanf("%d", &input); 12 if (input > 4 || input < 0){ 13 printf("You have entered an incorrect value.\n"); 14 check = false; 15 }else{ 16 for (i = 0; i < argc; i++){ 17 printf("argv[%hhu][%hhu]: %c\n", i, input, *(*(argv+i)+input)); 18 } 19 check = true; 20 } 21 } 22 return(0); 23 } 24
Analysis
I believe I have showed use of a tool or utility from the command line. I think there is always room to grow, especially when you are running low on time and waited to long to complete your opus. The method seems pretty solid, it shows an example of a working tool. Employing this enhancement will work because the program will run. I believe the course objective is very vital and strong as it stands.
Experiments
Experiment 1
Question
What would happen if I were to try to install a package with aptitude that does not exist?
Resources
My resource can be completely by testing this on a command line interface.
Hypothesis
I believe there will be some sort of error that is spit back at you from aptitude based on trying to throw arguments at other commands that do not exist.
State your rationale.
Experiment
I am going to test my hypothesis by executing the command: aptitude install blahblahblah
Data
lab46:~$ aptitude install blahblahblah E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?
Analysis
My hypothesis was not correct, because I got an error back not from aptitude but from another source. There is definitely more going on than I had conceived to begin with, I am getting a permissions error that I am not in root.
Conclusions
Based on the experiment, I can say that you cannot execute an aptitude install from a lab46 account that is not rooted.
Experiment 2
Question
Is there a way to use strings in the c language without using a library?
Resources
http://www.dfstermole.net/OAC/hstrings.html “In C, a string is stored as a null-terminated char array. This means that after the last truly usable char there is a null, hex 00, which is represented in C by '\0'. The subscripts used for the array start with zero (0). The following line declares a char array called str. C provides fifteen consecutive bytes of memory. N.B. Only the first fourteen bytes are usable for character storage, because one must be used for the string-terminating null.”
But this source showed an include of:
“#include <string.h>”
Hypothesis
Based on what I have read, I do not believe it is possible to use strings without an include file.
Experiment
To test my theory I will do more research and attempt to define a variable as type String.
Data
String x = "this is a string";
This code gave me an error that String is undefined. This leads me to believe that without the string include library, strings do not work in c as defined in other languages by the above.
Analysis
My hypothesis was correct, and the test examples show this.
Conclusions
I can get out of this experiment that to work with Strings in c, you have to include the String.h library.
Experiment 3
Question
Can the traffic of the irc between unix and csci be controlled by active users engaged in conversation?
Resources
For resources, I used a friend of mine from my hpc and c/c++ class named Josh to be the other active user in the irc to troll conversations with.
Hypothesis
I do believe that the irc traffic can be indeedly manipulated by active users by making conversation in only certain channels at different points in time.
To rationale this, we conducted conversations in different irc channels and the masses of the users seem to have flocked to those channels for help instead of the usual channels that the questions should be prompted in.
Experiment
How are you going to test your hypothesis? What is the structure of your experiment?
Data
The data can be viewed through the many troll of such conversations in the irc logs.
Analysis
My hypothesis was correct, the masses of the users did change to channels that were more active to ask their questions in.
Conclusions
I can now, in conclusion, manipulate the irc channels with a friend in anyway possible, maybe even to take over the world! *Throws to bwammm sound on youtube from inception* http://www.youtube.com/watch?v=h4a3y7xetJY
