This is the first day of class.

An important thing introduced to the class today was the class website.

• http://lab46.corning-cc.edu/haas/fall2013/cprog - for C and C++

This page is important because it contains all the tasks for the semester, and it serves as a central hub for all notes in the class.

The actual place where the magic happens. Lab46 is the server that we must ssh into in order to do class work.
In order for me to get into the server I have to use a program called putty.

Once Installed its very simple to get to the server.

• I simply type in the lab46.corning-cc.edu on port 22 and click open.
• At the prompt

login as :

• Enter your lab 46 user name

password : 

• Enter your lab 46 password
• After all of that I am into the lab. Which looks like this with the MOTD

 __         _     _ _   __   . . . . . . . . . . . . . . . . . . . . . . . . .
|  |   __ _| |__ / | |_/ /   . Basic System Usage:  Type 'usage' at prompt   .
|  |__/ _` | '_ \\_  _/ _ \  . Events and News:     Type 'news' at prompt    .
|_____\__,_|_.__/  |_|\___/  . Broken E-mail?       Type 'fixmail' at prompt .
---------------------------  . Check Lab46 Mail:    Type 'alpine' at prompt  .
c o r n i n g - c c . e d u  . . . . . . . . . . . . . . . . . . . . . . . . .

 Lab46 is the Computer & Information Science Department's Student Development
 Server for Computer-related coursework, projects, and exploration.  For more
 information, please check out:
  .. .  .    .        .                .                .        .    .  . ..
 .  Lab46 Web Page:       http://lab46.corning-cc.edu/                       .
 .  Lab46 Help Form:      http://lab46.corning-cc.edu/help_request           .
 .  Help E-mail:          haas@corning-cc.edu or wedge@lab46.corning-cc.edu  .
  .. .  .    .        .                .                .        .    .  . ..
No mail.

• I have used unix systems before, but I am lost when it comes to using one for coding and compiling.
• Getting used to working in a GUI-less environment for much of the class.

• Today we learned about GNU
• GNU - GNU not UNIX GNU created collection of tools
• Diagram given to us by Joe the hierarchy of coding

1. c - higher level
2. translate ~ compile ~ gcc
3. processor

• instruction set
• machine code referred to as assembly
• lower level programming

• We created a program to display “Hello World” using a compiler called GCC.

int main (int a, char **){
printf ("Hello World!!!");
}

• This alone is not enough to get GCC to be able to compile the program.
• We have to add a bit of code to be beginning of the program for it to work.
• If we include “# include <stdio.h>” at the begining then it should work.
• stdio is the standard IO file

GCC manual gcc.gnu.org

• -W ~ shows warnings when compiling
• -Wall - shows all warnings
• gcc -Wall -o “output file” “c file name”

• ; = statement terminator
• { } = block or group statements
• ( ) = Function
• ? mark = keeps the value of the last command
• && = logical and only true when both true

• I am struggling to wrap my head around just how C works. I have dealt with other coding languages before, but they actually made sense.
• Learning the whole case sensitive commands is also difficult for me.

GCC manual gcc.gnu.org section 3 look at ~ see it goes through phases 1: preproccessing 2: compilling 3: assembling 4: linking

• see if you can figure out command file name extensions for things to do with gcc
• look at the extensions for all four parts

• Shell in UNIX called bash
• c environment is ran within shell environment using ./
• cant run c programs without OS obviously
• in bash a dash means an argument

• The class repository is a version controlled storage system for keeping files of any kind.
• We can return to any stage in the file's life cycle.
• Great for in case our program stops working, we can roll back
• This is a distributed revision control system - you get your files from the server but you can serve the server from a terminal location using this system

lab46:~$ hg help

• General Help file for the mercurial repository

lab46:~$ mv src src.bak

• This renames the folder src to src.bak so that we have no issues during initialization.

lab46:~$ mkdir src

• This makes a new folder called src to replace the old

lab46:~$ hg clone http://www/hg/user/(username) ~/src

• This clones the mercurial repository at lab 46 to our personal src directory

lab46:~$ hg clone http://lab46.corning-cc.edu/hg/user/(username) ~/src

• This clones the mercurial repository at lab46 to our off campus computer at the src directory

lab46:~$ cd src

• Changes the current location to src directory

lab46:~$ lab46:~/src$ mv ~/src.bak/* ~/src/

• This moves the contents of the old src (src.bak) to our new src folder

lab46:~/src$ rmdir ~/src.bak

• Deletes the old src folder (src.bak)

• The name of the settings file for mercurial is hgrc
• The file is located in /src/.hg
• We need to change a few settings for it to work how we want

lab46:~/src$ vi .hg/hgrc

• Opens the file we want located in /src/.hg

[paths]
default = http://www/hg/user/(lab46username)
[web]
push_ssl = False
allow_push = *

[ui]
username = (your real first name followed by last name, space separated) <(lab46username)@lab46.corning-cc.edu>

[auth]
lab46.prefix = http://www/hg/user/(lab46username)
lab46.username = (lab46username)
lab46.schemes = http

• These settings are important so that we get the right sync

lab46~/src$ vi .hgignore

• Tells what types of files or directories to ignore when syncing so that undesirables don't show up in our repos.
• With this setup is complete and we are ready to sync

• Before anything can happen, we should check to see if there were any files added or changed in our repo

lab46:~/src$ hg status

• If anything had newly created and hadn't been tracked, it would have a ? mark in-front of it

• If we want the system to track the files for changes then we have to add them

lab46:~/src$ hg add

• If anything was added we would get a list back for example

lab46:~/src$ hg add
adding pokemon.c
lab46:~/src$

• If we did a “hg status” now, we would see the files listed with an “A” in-front of them representing Added

• In order for the system to actually track changes on files, we need to make a snapshot of the file. This is where committing comes in

lab46:~/src$ hg commit -m "(something to note about the commit that can be easily referenced)"

• This pushes the snapshot with an easily referenced log title
• To Take it one step further we need to send the changes to the remote server

lab46:~/src$ hg push

• You will be asked for your lab46 password and username, but username may be auto filled because of the hgrc file settings

http authorization required
realm: Lab46/LAIR Mercurial Repository (Authorization Required)
user: <lab 46 user name>
password: <lab 46 password>
pushing to http://www/user/<lab 46 user name>
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added <#> changesets with <#> change to <#> file

• If working in a situation where you are not the only person working on the files, then you would need to pull changes from the repository
• This generally works the same way as push, you are prompted for your lab46 username and password.\
• The command to pull is pretty obvious

lab46:~/src$ hg pull

• The changes will not show up until another command is issued

lab46:~/src$ hg update

• I have dealt with revision control systems before, being that I have had a class with Joe. When I had my class with joe, we used a GUI for the file syncing. Getting used to the syncing with a CLI is going to be a difficult adjustment.
• I also host a cloud service of my own using owncloud which is much like this, but I am going to try out syncing the class repo to my raspberry pi. I am not sure if I can though, but it is worth a shot. A port might be blocked preventing me from doing so, but I noticed the guide suggested doing so.

There were lots of things covered today the primary thing was data-types

• There are many types data-types

1. char ~ short for character has a dual purpose of being able to display character data
2. short int ~ short integer ~ describes a small scale integer
3. Int ~ integer ~ a thing that represents a whole number
4. long int
5. long long Int

• Signed and Unsigned versions of all exist
• One will be assumed automatically
• if you want it to be signed then it has to be + or negative numbers
• if you care that there is a sign then specify it

1. float
2. double
3. long double

1. Pointer Types ~ memory variables not really a thing that stands by themselves utilize the existing types ~ describing the region of memory that is pointing at something with specified property

1. Arrays ~ all of the other types can be represented as an array homogenous in an array every element needs to be of the same data type
2. Structures (struct) ~ heterogeneous can be of any types

1. Integer array is no different than having separate integer storage points
2. Consider the performance requirements of your program and try to keep them reasonable even with the limits of memory being pushed daily to extreme ends. Proper coding is a must
3. most programing books for c use argc argv as their examples
4. main has the ability to communicate with the system

Example : int main (int argc, char ** argv)

1. argc is an argument count
2. when ever you see a * that is not there for multiplication it denotes use of pointers
3. with the program knowing what it was called at run time, it can behave differently depending on how it was called

• \0 nul terminator ~ its how string termination is determined ~ translates to an asci character
• \n new line ~ most used
• \b back over the characters
• \a
• \l clear screen sometimes
• \f
• \t tab ~ second most used

• Having the source code to the program allows you to control the entire program to your needs.
• There are two specific types of source code

1. source code portability ~ when you have the source code not only can you run it on other systems but you can fix it and enhance it for your own needs
2. binary code portability ~ no system requirement but needs a specific program to help

• Two questions to ask about anything in programming

1. How much storage does it use?
2. What are the range of values we can store in them?

• Because of this it is always a good idea to

1. declare the existence of the variable
2. always a good thing to initialize your variable

• printf is formatted text
• every string has a nul terminator in it of \0 its hidden non printable character
• % sign is a substitution that is about to take place in a printf
• %d = e
• %v = f
• %c = g
• substitution happens at order of things
• %hhu means half half unsigned integer which means char
• %hu means half unsigned integer
• %u unsigned integer
• %hd means half signed integer
• %lu means
• %lu means

#include <stdio.h>
int main( )
{
    signed char sc;
    unsigned char uc;
    sc = 0;
    uc = 0;
    printf("an unsigned char is %hhu bytes \n", sizeof(uc));
    printf("lower bound is % hhu \n", uc);
    printf ("upper bound is % hhu \n", (uc - 1));
    return(0);
}

• This will return the values of the unsigned char

• This is really stepping into the unknown for me.
• I have never really thought of the actual size of things.
• I do not understand the whole unsigned and signed stuff yet
• Hopefully it will become clear with time

• I was able to create two programs. One for finding unsigned values, and one for finding signed values

  1 #include <stdio.h>
  2 int main( )
  3 {
  4     unsigned char uc=0;
  5     unsigned short int us=0;
  6     unsigned int ui=0;
  7     unsigned long int ul=0;
  8     unsigned long long int um=0;
  9     //unsigned char
 10     printf("A unsigned char is %d byte\n",sizeof(uc));
 11     printf("Lower bounds is %hhu\n", (uc));
 12     printf("Upper bounds is %hhu\n\n", (uc-1));
 13     //unsigned short
 14     printf("A unsigned short is %d bytes\n",sizeof(us));
 15     printf("Lower bounds is %hu\n", (us));
 16     printf("Upper bounds is %hu\n\n", (us-1));
 17     //unsigned int
 18     printf("A unsigned int is %d bytes\n",sizeof(ui));
 19     printf("Lower bounds is %u\n", (ui));
 20     printf("Upper bounds is %u\n\n", (ui-1));
 21     //unsigned long
 22     printf("A unsigned long is %d bytes\n",sizeof(ul));
 23     printf("Lower bounds is %lu\n", (ul));
 24     printf("Upper bounds is %lu\n\n", (ul-1));
 25     //unsigned long long
 26     printf("A unsigned long long is %d bytes\n",sizeof(um));
 27     printf("Lower bounds is %llu\n", (um));
 28     printf("Upper bounds is %llu\n\n", (um-1));
 29     return(0);
 30 }

• When ran it returns

A unsigned char is 1 byte
Lower bounds is 0
Upper bounds is 255

A unsigned short is 2 bytes
Lower bounds is 0
Upper bounds is 65535

A unsigned int is 4 bytes
Lower bounds is 0
Upper bounds is 4294967295

A unsigned long is 8 bytes
Lower bounds is 0
Upper bounds is 18446744073709551615

A unsigned long long is 8 bytes
Lower bounds is 0
Upper bounds is 18446744073709551615

• Working program for finding signed values

  1 #include <stdio.h>
  2 int main( )
  3 {
  4     signed char sc=0;
  5     signed short int ss=0;
  6     signed int si=0;
  7     signed long int sl=0;
  8     signed long long int sm=0;
  9     //signed char
 10     printf("A signed char is %d byte\n",sizeof(sc));
 11     printf("Lower bounds is %hhd\n", ((unsigned char)(sc-1)/2)+1);
 12     printf("Upper bounds is %hhd\n\n", ((unsigned char)(sc-1)/2));
 13     //signed short
 14     printf("A signed short is %d bytes\n",sizeof(ss));
 15     printf("Lower bounds is %hd\n", ((unsigned short)(ss-1)/2)+1);
 16     printf("Upper bounds is %hd\n\n", ((unsigned short)(ss-1)/2));
 17     //signed int
 18     printf("A signed int is %d bytes\n",sizeof(si));
 19     printf("Lower bounds is %d\n", ((unsigned int)(si-1)/2)+1);
 20     printf("Upper bounds is %d\n\n", ((unsigned int)(si-1)/2));
 21     //signed long
 22     printf("A signed long is %d bytes\n",sizeof(sl));
 23     printf("Lower bounds is %ld\n", ((unsigned long)(sl-1)/2)+1);
 24     printf("Upper bounds is %ld\n\n", ((unsigned long)(sl-1)/2));
 25     //signed long long
 26     printf("A signed long long is %d bytes\n",sizeof(sm));
 27     printf("Lower bounds is %lld\n", ((unsigned long long)(sm-1)/2)+1);
 28     printf("Upper bounds is %lld\n\n", ((unsigned long long)(sm-1)/2));
 29     return(0);
 30 }

• When used it displays

A signed char is 1 byte
Lower bounds is -128
Upper bounds is 127

A signed short is 2 bytes
Lower bounds is -32768
Upper bounds is 32767

A signed int is 4 bytes
Lower bounds is -2147483648
Upper bounds is 2147483647

A signed long is 8 bytes
Lower bounds is -9223372036854775808
Upper bounds is 9223372036854775807

A signed long long is 8 bytes
Lower bounds is -9223372036854775808
Upper bounds is 9223372036854775807

• bin = exe
• in UNIX you dont have file name extensions on a lot of things

• Create a CMD Shortcut
• right click on a cmd shortcut
• go to the properties
• go to the target
• if you leave the start in blank, then the start in section uses the current working directory instead

• cmd /? you
• in UNIX you have -h and in windows you have /?
• in windows you use a \ for a path separator and / is an option
• in windows you call scripts files batch files or .bat

• environment is the memory space in which the processes are working in
• set ~ spits out all environment variables
• all environment variables have an equal sign
• you cant have spaces in environment variables
• on left side is the environment name and on the right is the variable

two major types of commands in a command line interpenetrate

1. internal (Unix and Linux ~ built into the command line inter - knows where to go )
2. external

• if it cant find it it searches for a file with that name and the file is executable, it will execute it
• in windows cmd looks in the current directory first, unix / linux does not look in the current directory
• path = something sets the path directory

• there is not a lot to the language of c and c++

• look at section 5
• You might see someone start a hello world program that starts
• Void main ( Void ) {
• }
• vs
• Int main (int a , char ** ) {
• }
• Void is a data type but nothing is something so you have to have a data type for nothing
• what is the answer to y = f(x)?
• not enough information. can agree it is a function. is it a call or a definition?
• this is the notion of a function call
• reason its hard to decide is that the function has never been defined
• if i see a set of parenthesis and something to the left its not always a function , it could be part of order of operations
• a(b)+c(d); is it a definition or a function call
• functions exponents roots multiplication division addition subtraction logical operations
• Functions Have
• 1)Name
• 2)Input
• 3)Output
• Variables Have
• 1)Name
• 2)Value
• 3)Data type~ tells us how much memory we have to store values
• try different combinations
• argc is the count
• argv is the vector
• we can nest function calls, there are limits on how many levels you can nest, a max on grouping with parentheses
• numerical limits and sizes
• almost all c keywords are small list
• basic things you want from any language you learn
• 1) learn basic output
• 2) learn basic input
• section 1719 is input out stdio
• C was born in a unix type environment
• i/o is a stream of bits

• fprintf ~ print to specific file
• fprint ~ print
• scanf ~ input

1. UNIX / Microsoft Command Reference ~ a Cheat Sheet equivalence
2. mingw bin folder file descriptions
3. gcc options for 1) preprocess 2) compile 3) assemble 4) link
4. figure out the other switches for these and how they would work
5. file name extensions too ~ gcc documentation on bitbucket section 3 of manual
6. 4 ~ 9899 section 5 pull out what we find most important
7. freestanding hosted arguments reference for main( ) 5 9899 section 6
8. language for 9899 section 7 library
9. input output

• Switching back to a windows environment (At Joes Request) has caused me a lot of confusion
• MinGW has yet to install right for me, and I really hop e I can avoid using it.

• We continued work on a program to list the values of a Signed Char

#include <stdio.h>
int main( )
{
    signed char sc;
    unsigned char uc;
    sc = 0;
    uc = 0;
    printf("a signed char is %hhu bytes\n", sizeof(sc));
    printf("lower bound is %hhd\n",((unsigned char)(uc-1)/2)+1);
//    printf("upper bound is %hhd\n",((unsigned char)(uc-1)/2));
    printf("upper bound is %hhd\n", 0xFFFF & 0x80);
    return(0);
}

• Lists the size of a signed char, lower bound, and upper bound

• /usr/include has the system header directory. headers that can be used for programming
• anything with a # is a preprocessor
• when you do # something its actually like inserting the entire code into yours
• do include statements at the top
• #include “ filename” makes it break off into a directory specific file

• The signed and unsigned chars are starting to make a little sense
• I am still struggling with remembering the commands to sync our repo

• Sizes can change throughout the years ( Int or long int could have changed )
• It is important to know if they have changed so that you can create things that work with the system
• the header files will talk about the limits of the system
• be mindful that the header files will not accurately reflect system limits. they reflect the standard

• Display things with printf
• printf() - not a keyword
• keywords - base commands available to us
• c has a set of keywords avalible to them Examples :

1. short
2. int
3. char
4. all the variable types
5. * - / * ^ &

• By combinding all of them you make programs

• printf() lets us display information ~ information in man 3 printf - is a family of functions - at the top of the manual it shows you the list of functions covered in the manual- the first line under the synopsis is that it tells you the include files you need to include to use the function
• fprintf and sprintf most likely to be used
• scanf() lets us get information from the user
• int main ( ) - main is a function we are creating
• malloc( ) ~ gives you a memory address called a return value, when it is done we capture it ~ gives you raw memory

• always good to put your variables at the top of the program for readability
• if you like indentation always use 4 spaces, if you like tab always use tab
• you can not name a variable after a keyword
• with scanf you need to put the address of the storage location not the variable
• a string of characters is also called an array of characters in -c
• %s please interperate input as string data
• %c prints out ascii character of value
• address is the pointer without the star
• & - give location of address
• all strings in c need a mechanism to know when the string ends \0 also known as the null terminator is needed to let c know that a string is over

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 int main( )
  4 {
  5     char *name,fi;
  6     name=NULL;
  7     fi=0;
  8     unsigned char age=0;
  9     printf("Please enter your name");
 10     name=(char*)malloc(sizeof(char)*20);
 11     scanf("%s", name);
 12     printf("%s, what is your age?",name);
 13     scanf("%hhu",&age);
 14     fi=*(name+0);
 15     printf("%s, your initial is %c (%hhu) and you are %hhu years old\n",name    ,fi,fi,age);
 16     return(0);
 17 }

• This program asks for our name and our age. It pulls out the first letter of our name.

  * "When writing IF statements it is good to remember"
  - "> greater than"
  - "< less then"
  - ">= greater than or equal to"
  - "<= less than or equal to"
  - "== Check equality ( is this equal to)"
  - "!= not equals"
  - "= sets equality"
  - "if statements do not need a semicolon"
  - "you can have if statements"
  - "else statements"
  - "with else if"
  - "have have exactly 1 if"
  - "can have only "
  - "exactly 1 else"
  - "0 or more else if"
  - "if(0) - true"
  - "if(1) - false"

1. do while - run through the loop and then see if it should run again
2. while
3. for - need starting value - setting start value - second part is how long do we want to loop - third part

We learned about things with I but they cant be posted in wiki syntax

• We created a program to count the arguments on the command line, and then express them with different output styles.
• running the program with the ./program-name then the count of the values after the program

• Today we learned about a image manipulation library called GD.
• GD is often used with things like php
• C programs can be written to utilize the package.
• http://lab46.corning-cc.edu/~jkosty6/snowmanhouseccc.png is an example of a program we were asked to create

  1 # include <stdio.h>
  2 # include <gd.h>
  3 # define BLACK 0
  4 # define RED 1
  5 # define GREEN 2
  6 # define BLUE 3
  7 # define WHITE 4
  8 # define YELLOW 5
  9 int main()
 10 {
 11     FILE *out; // lets us interact with files in this case an output file
 12     char outfile[]="/home/jkosty6/public_html/snowmanhouseccc.png";
 13     gdImagePtr img;
 14     unsigned int color[5];
 15     unsigned short int high,wide,x;
 16     wide=800;
 17     high=600;
 18     img=gdImageCreate(wide,high);
 19     color[BLACK]=gdImageColorAllocate(img,0,0,0);
 20     color[RED]=gdImageColorAllocate(img,255,0,0);
 21     color[GREEN]=gdImageColorAllocate(img,0,255,0);
 22     color[BLUE]=gdImageColorAllocate(img,0,0,255);
 23     color[WHITE]=gdImageColorAllocate(img,255,255,255);
 24     color[YELLOW]=gdImageColorAllocate(img,255,255,0);
 25     gdImageFilledRectangle(img,0,0,wide-1,high-1,color[BLACK]);
 26     gdImageFilledRectangle(img,wide/3,high/1,wide/1,high/3, color[YELLOW]);
 27     gdImageFilledRectangle(img,wide/3,150,wide/1,200, color[BLUE]);
 28     gdImageFilledRectangle(img,300,400,400,500, color[BLACK]);
 29     gdImageFilledRectangle(img,650,400,750,500, color[BLACK]);
 30     gdImageFilledRectangle(img,450,400,600,high-1, color[BLACK]);
 31     gdImageFilledArc(img, 90, 90, 180, 180, -270, -90, color[RED], gdArc);
 32     gdImageFilledArc(img, 180, 90, 180, 180, -270, -90, color[RED], gdArc);
 33     gdImageFilledArc(img, 270, 90, 180, 180, -270, -90, color[RED], gdArc);
 34     gdImageFilledArc(img, 90, 300, 100, 100, 360, 0, color[WHITE], gdArc);
 35     gdImageFilledArc(img, 90, 400, 130, 130, 360, 0, color[WHITE], gdArc);
 36     gdImageFilledArc(img, 90, 500, 180, 180, 360, 0, color[WHITE], gdArc);
 37     out=fopen(outfile, "wb");
 38     gdImagePngEx(img,out,-1);
 39     fclose(out);
 40     gdImageDestroy(img);
 41     return(0);
 42 }

• Is that the code looks like
• -lgd at the end compiles

• I have used GD before when I was hosting a coppermine website, but I never actually thought I could use it in this way. It is pretty challenging to use.

• Loops are very simple to set up in C

int i;
for (i=0; i<10;i++)
{
    printf("%d\n",i);
}

• prints out characters 0 to 9 then exits
• for(start, condition, step) ~ numeric based loop, know where you start, know where you end, tell it how you wish to get there
• for portion does not end with a ;
• when you loop, you loop based on your looping variable
• in this case our looping variable is i
• second part of the thing is our loop as long as section ( i<10)
• third part is how we get there (i++)
• loop allows us to repeat a block of code

• Loops can be used in GD in order to generate faster pictures
• We were asked to generate a checker board

http://lab46.corning-cc.edu/~jkosty6/classgd.png

• I was able to get this to draw using the code

  1 # include <stdio.h>
  2 # include <gd.h>
  3 # define BLACK 0
  4 # define RED 1
  5 # define GREEN 2
  6 # define BLUE 3
  7 # define WHITE 4
  8 int main()
  9 {
 10     FILE *out;
 11     char outfile[]="/home/jkosty6/public_html/classgd.png";
 12     gdImagePtr img;
 13     unsigned int color[5];
 14     unsigned short int high,wide,x,y;
 15     wide=641;
 16     high=641;
 17     img=gdImageCreate(wide,high);
 18     color[BLACK]=gdImageColorAllocate(img,0,0,0);
 19     color[RED]=gdImageColorAllocate(img,255,0,0);
 20     color[GREEN]=gdImageColorAllocate(img,0,255,0);
 21     color[BLUE]=gdImageColorAllocate(img,0,0,255);
 22     color[WHITE]=gdImageColorAllocate(img,255,255,255);
 23     gdImageFilledRectangle(img,0,0,wide-1,high-1,color[BLACK]);
 24 //      {
 25 //      for(x=0;x<8;x++)
 26 //      for(y=0;y<8;y++)
 27 //          if ((x + y) % 2 == 0)
 28 //              {
 29 //              gdImageFilledRectangle(img,(80*x)+5,(80*y)+5,(80*x)+75,(80*y)+75,color[BLUE]);
 30 //              }
 31 //          else
 32 //              {
 33 //              gdImageFilledRectangle(img,(80*x)+5,(80*y)+5,(80*x)+75,(80*y)+75,color[RED]);
 34 //              }
 35 //          }
 36     gdImagePngEx(img,out,-1);
 37     fclose(out);
 38     gdImageDestroy(img);
 39     return(0);
 40 }

• After running it a few times I get segmentation faults, I hope I can fix this

After playing with GD for a few days, I am finding it to be more difficult that its worth.

I have figured out what my problem was. I had deleted the line 36

  1 # include <stdio.h>
  2 # include <gd.h>
  3 # define BLACK 0
  4 # define RED 1
  5 # define GREEN 2
  6 # define BLUE 3
  7 # define WHITE 4
  8 int main()
  9 {
 10     FILE *out;
 11     char outfile[]="/home/jkosty6/public_html/classgd.png";
 12     gdImagePtr img;
 13     unsigned int color[5];
 14     unsigned short int high,wide,x,y;
 15     wide=641;
 16     high=641;
 17     img=gdImageCreate(wide,high);
 18     color[BLACK]=gdImageColorAllocate(img,0,0,0);
 19     color[RED]=gdImageColorAllocate(img,255,0,0);
 20     color[GREEN]=gdImageColorAllocate(img,0,255,0);
 21     color[BLUE]=gdImageColorAllocate(img,0,0,255);
 22     color[WHITE]=gdImageColorAllocate(img,255,255,255);
 23     gdImageFilledRectangle(img,0,0,wide-1,high-1,color[BLACK]);
 24         {
 25         for(x=0;x<8;x++)
 26         for(y=0;y<8;y++)
 27             if ((x + y) % 2 == 0)
 28                 {
 29                 gdImageFilledRectangle(img,(80*x)+5,(80*y)+5,(80*x)+75,(80*y)+75,color[BLUE]);
 30                 }
 31             else
 32                 {
 33                 gdImageFilledRectangle(img,(80*x)+5,(80*y)+5,(80*x)+75,(80*y)+75,color[RED]);
 34                 }
 35             }
 36     out=fopen(outfile, "wb");
 37     gdImagePngEx(img,out,-1);
 38     fclose(out);
 39     gdImageDestroy(img);
 40     return(0);
 41 }

Today we learned a lot about arrays

• array[0] same as *(array+0) ~ access first element of an array
• Is a homogeneous composite variable qualifier type
• arrays modify an existing data-type
• you are taking a type and making many of them, in that sense it is a composite type
• a character array must contain characters only
• with an array it is under one common name and we can arithmetically reach what we want
• when you see arrays you almost always are dealing with loops
• we can make arrays out of anything , int , char, gd points
• first point of an array is index 0, the first element is the first thing you encounter which is always 0
• the second element is the first offset which would be 1, when we look at memory addresses whats actually happening in memory is that if it is an int then we have 4 bytes per offset in an array
• when we tell it to move in 1 or 2 in an array it moves in what ever the unit value of our array is, if its int, we move in 4 each time
• we use arrays to store common data, things we want to put together. coordinates could work

Example

• you have 3 int sized boxes located right after each other
• because there are many, its a composite
• because it gives us many it must be the same, int array must be all integers

• with individual variables with 1 scaler, if w wanted to deal with 3 variables with 3 values we would us scalers
• if we wanted 3 int sized memory but call them one name we would use a array, same amount of space as separate scalers
• we can access them using one name using an array instead of a scaller
• we can simplify our code by using only one name instead of many, we use name plus offset
• with this we can create loops to access each element in an array, if we used scalers we would need to use if statements to hit each separate named variables

===GD Arrays==-

• gd allows us to create polygons by using arrays
• this is like a datatype ~ gdpoint
• its doing a struct ~ struct is like an array but the values do not need to be the same
• Example

gdPoint triangle[3]; ~ array of 3 gd points
triangle[0].x = wide/2;
triangle[0].y = 0;
triangle[1].x =0;
triangle[1].y =high-1;
triangle[2].x =wide -1;
triangle[2].y = high -1;

• This draws a 3 sided polygon

• From everything we learned, we were told to
• 1. draw triangle ~ http://lab46.corning-cc.edu/~jkosty6/snowmanhouseccc.png
• 2. draw house made of polygons ~ http://lab46.corning-cc.edu/~jkosty6/polygonhouse.png
• 3. draw 3 other polygons with number of sides greater than 4 ~ http://lab46.corning-cc.edu/~jkosty6/polygons.png
• 4. draw a clock face - triangles or something at all of the positions. set the time with trisangles ~ http://lab46.corning-cc.edu/~jkosty6/clock.png

Drawing with GD using exact x and y values with arrays is actually easier in my opinion than the alternative

Today we just finished working on our GD pictures.

• Today we learned about shifts

1. » logical right shift
2. « logical left shift

  1 #include <stdio.h>                                                          
  2     int main ()
  3     {
  4     int a =5;
  5     printf("%d\n",a);
  6     a=a|6;
  7     printf("%d\n",a);
  8     a=a&9;
  9     printf("%d\n",a);
 10     a=!a;
 11     printf("%d\n",a);
 12     a=a^7;
 13     printf("%d\n",a);
 14     return(0);
 15     }
 16 

• shifts the data to get to the right location
• usually deals with external devices
• bitwise or
• inclusive either must be true
• exclusive one must be true but not both
• Example

  1 #include <stdio.h>                                                                                                                      
  2 #include <stdlib.h>
  3 
  4 int getval(int,int); ~ prototyping
  5 int main()
  6 {
  7     int i,x,u,l;
  8         printf("Enter a number:");
  9         scanf("%d",&i);
 10         srand(i);
 11         printf("Give me the highest number.");
 12         scanf("%d",&u);
 13         printf("Give me the lowest number.");
 14         scanf("%d",&l);
 15 for (i=0;i<12;i++)
 16 {
 17     x=getval(u,l);
 18     printf("%d ",x);
 19 }
 20     printf("\n");
 21 return(0);
 22 }
 23 int getval (int top, int bottom)
 24 {
 25     int result;
 26     result = rand() %top + bottom;
 27 return(result);
 28 } 

We created a program to tell you the ascii value of something, and changing a letters case

  1 #include <stdio.h>
  2 int main()
  3 {
  4     char x=0;
  5     char y=0;
  6         printf("Enter a number (0-255): ");                                 
  7         scanf("%hhu", &x);
  8         printf("Enter a character: ");
  9         scanf("%c", &y);
 10         printf("x is numerically %hhu and characterally %c \n",x,x);
 11         scanf("y is numerically %hhu and characterally %c \n",y,y);
 12         printf("x+48 characterally is %c \n", (x+48));
 13         scanf("y+32 character is %c \n", (y+32));
 14     return(0);
 15 }

enter in a data stream, stays behind in data stream

• line feed - unix - asci 10
• carriage return line feed - windows - 13 and 10
• carriage return - mac - 13
• we need to fix our program to take care of the enter
• getchar(); gets rid of the extra new line command
• to get to ascii version of a number add 48
• to go from upper to lower case ascii add 32
• scanf
• fscanf read from file
• sscanf read from string
• getchar
• fgetc read character from file
• fgets read multiple characters from file
• man 3 fgetc

• print f and scan f are just function calls
• we can go and find them inside the c library
• keywords are not functions
• with gd we are looking into a bunch of libraries
• we use a bunch of predefined functions
• we dont have to write as much in c so we can build sooner than later
• getval - function name
• thing to left of get val is a return type
• int getval (int top, int bottom - parameters - external bits of information that we can send or pass into the function
• get val passing by value
• x = getval(u,l)
• its taking the contents of u and putting them in top
• they are not the same variable
• they are seperate
• its just at this point they have the same value
• they dont reference the same memory location so they are seperate from eachother in almost every way with no way of causing conflicts or affecting each other beyond the starting point
• c does passing by address
• value vs reference
• lets say we wanted to pass top by address, we need to communicate the memory address using pointers
• if we made top a pointer in our function, we need to update our prototype to be an intiger pointer
• if we do memory references then they change together
• return a array char* to return
• gd is an api like an android dev kit

• First day we wrote a hello world program
• compile turns it into assembly
• A program such as

WIKI DOESNT LIKE MY CODE

• this program is over 800 lines after all the preprocessing
• it converts it to assembly language
• complex code could end up compiling slower than longer code
• its what you do, second is how much is there

• c code is portable but it has its limits
• opening a file on windows is different than on unix
• if you have a symble defined
• some symbols exist on the different systems only

• #include - inserts the files contents into your file
• #define
• # fdef
• #fndef
• #fndef
• #endif
• gcc -E hello.c |less shows all of the PPDs
• cd /usr/include ~ locations of all header files - system header directory
• it prevents the file from being included multiple times
• struct _IO_FILE; - global variable . everything can see it
• possics compliant code - can check for it and run if it is
• variable arguement - … - write functions that take as many arguements as you want
• gcc -S first.c

• struct - is a container variable except its different than an array but it can have different types
• io file is a type of struct
• every time you want to use an io struct you have to type struct and io
• typedef struct _IO_FILE FILE; - sets up an alias so that every time we type file, we get the other line
• struct is programable datatype
• FILE *out; - out is a file pointer

It was interesting to see just how long a code is after adding in the headerfiles

Today was the knowledge assessment. It was a little difficult at first, but when I really read the problems, I figured them out. Except the last one that blew my mind. A time based RNG

• object oriented program is just code organization and techniques you inflict on your code
• in C++ programming you take on the role of a manager and you manage your code
• up to this point we have been playing the role of the end developer we write from the ground up
• this role is still valid and has to be filled still
• people have to make subroutines
• object oriented makes managing these individual tasks easier to manage
• we can continue to be the end devs but wrapping in C++ around it
• with C++ you really dont write a C++ program, you outline a C program with C++ syntax

• arrays - are homogonous datatypes - means all the same type - many - every element must be the same- if an int every must be int - reference one name mulltiple values
• structs - or stuctures - heterogenous type - meaning they dont have to be the same, only have to be the same if you want them to be the same - reference one name - struct could contain any comibation of anuthing
• struct you have to identify it with the word struct

struct thing {
    int a;
    int b[20];
    float c;
    int d;
    short int e;
}; ~ one of the few times you need a semi colon after a closing bracket in C

struct thing stuff; ~ one thing from struct "thing" and we named it stuff
stuff.a =12;
stuff.b[ j ]='A'; ~ 

• gdpoint is a struct

#include <stdio.h>
int main( )
{
    int i,j,k;
    struct person {

        char name [24];

    char age;

    float height;

};
typedef struct person ID;
ID db [4];
for (i=0; i<4; i++)
{
    printf("Entry [%d] name : ");
    scanf("%s",ID[i].name);
    printf("age");
    scanf("%hhu",&(ID[i]age));
    printf("height : ");
    scanf ("%f",&(ID[i]height));
}
    
    //print it all back out
    return(0);
}

Structs have me at a loss, but I am sure I will know them soon enough

• in c you use gcc
• c++ you use g++
• .c for c files
• .cc .cpp .c++ .C for c++
• first C++ program

  1 #include <stdio.h>
  2 int main ( )
  3 {
  4     printf("Hello, world!\m");
  5     return (0);
  6 }

• most of the time all valid c code is valid c++ code
• pretty much all of c is in c++
• some of c is not included
• void * is not in c++
• all of our datatypes are still there
• with c++ we gain a few structs
• g++ -o helloplus hello.cc
• #include <cstdio> prefered c++ way of adding headerfiles

• class ~ the thing we define such a struct
• object ~ int a ~ int class and a is object ~
• classes have access control. allow or prohibit how people access parts of our data
• public: functions or variables we wish for people to have access to
• functions that are public that give you assess - assessor methods - method is fancy name for function
• constructor - class name no type with any peramiters
• in c you cant have two functions by the same name but in c ++ you can
• contructor is a special kind of function. every class can have one. dont have to have one. whati t does is let you run code upon extantionation
• private only accesavble to class

today we wrote a program with classes and structs to it dealing with the sides of a shape and then outputting them

Class square {
      public
            square( );
            void setside(int);
            int getside( );
            int area( );
            int perimeter( );
      private
            int x;
};
 
square :: square( )
{
      x=0;
}
void square :: setside(int side)
{
      x=side;
}
int square :: getside( )
{
      return(x);
}
int square :: area( )
{
      return(X * X);
}
int square :: perimeter( )
{
      return( 4 * x );
}
 
int main ( )
{
      square s1;
      square s2;
      s1.setside(4);
      s2.setside(12);
      printf("s1's side is %d\n", s1.getside( ));
      printf("s1's area is %d\n", s1.area( ));
      printf("s1's perimeter is %d\n", s1.perimeter( ));
      return(0);
}

• what if we had an array
• we have to create our own addition multiplication if we break it out
• we get to implement our own datatype
• we start by writing a header-file
• as we model this there are a few things at play
• the length of the number
• what do we want to represent in our bignum
• we can control how big we want it to be
• the other is that we can determine if its positive or negative
• the third is the base that we want to apply to it
• we could do a base of anything 17 18 or even the base 10 system that we are so accustom to using in our every day life

bignum.h
#ifndef _BIGNUM_H
#define _BIGNUM_H
class BigNum {

    public:

    BigNum( );

    BigNum(unsigned int);

    unsigned char getbase( );

    unsigned char getlength( );

    unsigned char getsign( );

    void SetBase (unsigned char);

    void SetLength (unsigned char);

    void SetSign (unsigned char);

    void zero( );

    void print ( );

    private:

    unsigned char base;

    unsigned char Length;

    unsigned char sign;

    unsigned char *data;

This week we continued work on our program, but this week we added the ability to increment our numbers.

• we read our numbers from left to right
• we have an issue of implementation with storage. do we want to store it from right to left or from left to right
• we read from left to right currently

I finally was able to get tape to work

#ifndef _STORAGE_H
#define _STORAGE_H

using namespace std;

class storage
{
    public:
        storage();
        int getCapacity();
        int getFree();
        int getUsed();

    protected:
        int load();
        void store(int);
        bool pos(int);

    private:
        int data[256];
        int used;
        int available;
        int loc;
};

#endif

#include "storage.h"
#include <iostream>

storage :: storage()
{
    int i;
    used = 0;
    available = 255;
    for (i = 0; i < 256; i++)
        data[i] = 0;
    loc = 0;
}

int storage :: getCapacity()
{
    return used + available + 1;
}

int storage :: getFree()
{
    return available + 1;
}

int storage :: getUsed()
{
    return used;
}

int storage :: load()
{
    return data[loc];
}

void storage :: store(int value)
{
    if (used < 255)
    {
        data[loc] = value;
        used++;
        available--;
    }
    else
        cout << "Error! Out of space!" << endl;

    if (value == 0)
    {
        used--;
        available++;

        if(used > 255)
            used = 255;

        if(used < 0)
            used = 0;

        if(available > 255)
            available = 255;

        if(available < 0)
            available = 0;
    }
}
bool storage :: pos(int location)
{
    bool retval = true;

    if ((location >= 0) && (location <= 255))
        loc = location;
    else
        retval = false;

    return retval;

#ifndef _TAPE_H
#define _TAPE_H
#include <iostream>
#include "storage.h"
class tape : public storage
{
    public:
        tape();
        int read();
        void write(int);
        void forward();
        void backward();
        void rewind();
        void setlabel(string);
        string getlabel();
        int getpos();

    private:
        string label;
        int position;
};

#endif

#include "storage.h"
#include "tape.h"
#include <cstdio>

tape::tape()
{
    position=0;
    pos(position);
    label="TapeYo";
}

int tape::read()
{
    return(load());
}

void tape::write(int num)
{
    store(num);
}

void tape::forward()
{
  if (position==255)
         {
            printf("You have reached the end of the tape!\n");
            position--;
            pos(position);
         }
else
    {
        position++;
        if (position==255)
            {
            printf("You have reached the end of the tape!\n");
            position--;
            pos(position);
            }
    }
}


void tape::backward()
{
  if (position==0)
         {
            printf("You have reached the end of the tape!!\n");
            position++;
            pos(position);
         }
else
    {
        position--;
        if (position==0)
            {
            printf("You have reached the end of the tape!\n");
            position++;
            pos(position);
            }
    }
}

void tape::rewind()
{
    while(position!=0)
    {
        position--;
    }

    pos(position);
}

void tape::setlabel(string labelstr)
{
   label=labelstr;
}

string tape::getlabel()
{
   return(label);
}

int tape::getpos()
{
    return(position);
}

#include <cstdio>
#include "tape.h"
#include <iostream>

using namespace std;

int main()
    {
    tape t;
    char choice;
    int tapeinputval;

while(choice!=113)
    {
    printf ("\n================================================\n");
    printf ("The Tape Is Currently At Position ");
    cout << t.getpos();
    printf ("\n\n");
    printf ("Please Choose A Command For The Tape To Take\n\n");
    printf ("f = move the tape forward\n");
    printf ("b = move the tape backward\n");
    printf ("r = rewind the tape\n");
    printf ("e = read what is stored at current position\n");
    printf ("w = write at current position\n\n");
    printf ("Use q to quit\n");
    printf ("================================================\n");
    cin >> choice;
    printf ("\n");
        switch(choice)
            {
            case 102:
                t.forward();
                printf ("The Tape Has Moved To Position ");
                cout << t.getpos();
                printf ("\n");
                break;
            case 98:
                t.backward();
                printf ("The Tape Has Moved To Position ");
                cout << t.getpos();
                printf ("\n");
                break;
            case 114:
                t.rewind();
                printf ("The Tape Has Moved To Position ");
                cout << t.getpos();
                printf ("\n");
                break;
            case 101:
                printf ("The Tape Is Currently At Position ");
                cout << t.getpos();
                printf (" and stored here is ");
                cout << t.read();
                printf ("\n");
                break;
            case 119:
                printf ("Please enter a value to store at current position \n");
                cin >> tapeinputval;
                t.write(tapeinputval);
                printf ("\nThis position now stores the value ");
                cout << t.read();
                break;
            case 113:
                return(0);
        }
    }
}

I managed to get increment and decrement to work. From these two things I can do almost anything

#include "bignum.h"

unsigned char BigNum::getBase()
{
        return(base);
}

void BigNum::setBase(unsigned char base)
{
        this -> base = base;
}

#ifndef _BIGNUM_H
#define _BIGNUM_H

class BigNum
{

public:
        BigNum();
        BigNum(unsigned char);
        unsigned char getBase();
        unsigned char getLength();
        unsigned char getSign();
        void setBase(unsigned char);
        void setLength(unsigned char);
        void setSign(unsigned char);
        void zero();
        void print();
        void increment();
        void decrement();
private:
        unsigned char base;
        unsigned char length;
        unsigned char sign;
        unsigned char *data;

};

#endif

#include "bignum.h"


unsigned char BigNum::getLength()
{
        return(length);
}

void BigNum::setLength(unsigned char length)
{
        this -> length = length;
}

#include "bignum.h"
#include <cstdio>
void BigNum::print()
{
        int i;


        for(i=0; i<length; i++)
        {
                printf("%d", *(data+i));
        }
        printf("\n");
}

#include "bignum.h"

unsigned char BigNum::getSign()
{
        return(sign);
}

void BigNum::setSign(unsigned char sign)
{
        this -> sign = sign;
}

#include "bignum.h"

void BigNum::zero()
{
    for(int i=0;i<length;i++)
    {
        *(data+i)=0;
    }
}

#include <cstdlib>
#include <cstdio>
#include "bignum.h"

BigNum::BigNum()
{
        length = 8;
        base = 10;
        sign = 0;
        data = (unsigned char*)malloc(sizeof(char)*length);
        this -> zero();
}


BigNum::BigNum(unsigned char length)
{
        this -> length = length;
        base = 10;
        sign = 0;
        data = (unsigned char*)malloc(sizeof(char)*this -> length);
        this -> zero();
}

void BigNum::increment()
{
    char carryvalue=1;
    {
        for(int i=0;i<length;i++)
        {
            char endresult = *(data+(length-1)-i);
            char addedvalue = endresult + carryvalue;
                if ((addedvalue > 9) && ((addedvalue%10)==0))
                    {
                    addedvalue = 0;
                    carryvalue = 1;
                    }
                else
                    {
                    carryvalue = 0;
                    }
                    *(data+(length-1)-i) = addedvalue;
        }
    }
}

void BigNum::decrement()
{
        char carryvalue=1;
    {
        for(int i=0;i<(length-1);i++)
        {
            char endresult = *(data+(length-1)-i);
            char subtractedvalue = endresult - carryvalue;
                if ((endresult <= 0) && (carryvalue == 1))
                    {
                    subtractedvalue = 9;
                    carryvalue = 1;
                    }
                else
                    {
                    carryvalue = 0;
                    }
                    *(data+(length-1)-i) = subtractedvalue;
        }
    }
}

Division is not done yet, but it is a work in progress.

#include "bignum.h"
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <cstdio>

using namespace std;

int main()
{
	int choice;
	printf("\n\n================================================================\n");
	printf( "How would you like to increment or decrement a number?\n");
	printf( "\n0 - Subtraction");
	printf( "\n1 - Addition");
	printf( "\n2 - Multiplication");
	printf( "\n3 - Division !! NOT WORKING - WORK IN PROGRESS !!\n\n"); // work in progress
	printf( "Your Choice is :");
	cin >> choice;
	BigNum num;
	num.setBase(10);
	int i,x;
	int loop1,loop2;
	int loop3,loop4;
	int loop5,loop6;
	int loop7,loop8;
	int sub1,sub2;
	int div1,div2;
	int z,w;	
		{
		if (choice ==3)
			{
			printf ("================================================================\n");
			printf ("\nDivision Mode\n");
			printf ("\nEnter Your First Number: ");
			cin >> div1;
			printf ("Enter Your Second Number: ");
			cin >> div2;
			printf ("\n================================================================\n");
			{
                if (div1 > div2)
                    {
                    loop7=div1;
                    loop8=div2;
                        {
						for(i=0;i<=loop7;i+=loop8);
							{
							num.increment()
							}
						//other division stuff not done
						num.print();
						}
					}
				else
					{
					loop7=div2;
					loop8=div1;
						{
						for(i=0;i<=loop7;i+=loop8);
							{
							num.increment();
							}
						//other division stuff not done
						}
                                              num.print();
					}	
			}
		}
		else if (choice == 2)
			{
			printf ("================================================================\n");
			printf ("\nMultiplication Mode\n");
			printf ("\nEnter Your First Number: ");
			cin >> loop5;
			printf ("Enter Your Second Number: ");
			cin >> loop6;
			printf ("\n================================================================\n");
			{
			for(i=0;i<loop5;i++)
				{
				for(x=0;x<loop6;x++)
					{
					num.increment();
					}
				}
			}
				num.print();
		}
		else if (choice == 1)
			{	
			printf ("================================================================\n");
			printf ("\nAddition Mode\n");
			printf ("\nEnter Your First Number: ");
			cin >> loop1;
			printf ("Enter Your Second Number: ");
			cin >> loop2;
			printf ("\n================================================================\n");
			{
			for(i=0;i<loop1;i++)
				{
				num.increment();
				}
			for(i=0;i<loop2;i++)
				{
				num.increment();
				}
			}
				num.print();
		}
		else
			{
			printf ("================================================================\n");
			printf ("\nSubtraction Mode - Largest of The Two Numbers Sorted As Minuend\n");
			printf ("\nEnter Your First Number: ");
			cin >> sub1;
			printf ("Enter Your Second Number: ");
			cin >> sub2;
			printf ("\n================================================================\n");
				{
				if (sub1 > sub2)
					{
					loop3=sub1;
					loop4=sub2;
						{
						for(i=0;i<loop3;i++)
							{
							num.increment();
							}
						for(i=0;i<loop4;i++)
							{
							num.decrement();
							}
						}
							num.print();
				}
				else
				{
					loop3=sub2;
					loop4=sub1;
					{
					for(i=0;i<loop3;i++)
						{
						num.increment();
						}
					for(i=0;i<loop4;i++)
						{
						num.decrement();
						}
					}
						num.print();
				}
			}
		}
	}
	return(0);
}

• Talked about how unix can be on many devices without even realizing it

1. Routers
2. Cars
3. Cellphones

• I myself have unix installed on my routers

An important thing introduced to the class today was the class website.

• http://lab46.corning-cc.edu/haas/fall2013/unix - for unix

This page is important because it contains all the tasks for the semester, and it serves as a central hub for all notes in the class.

• The lab46 server has an IRC server ~ great for collaboration and for messing around

1. Log onto a terminal
2. SSH Lab46 or lab46.corning-cc.edu if out of lab
3. screen
4. irssi
5. /server irc
6. /join csci
7. /join unix

• screen -r is used to rejoin the chat after leaving
• ctrl A + D leaves the chat system and returns you to home
• screen -ls tells you about your current screen
• alt + number to switch irc servers

• Nothing so far has actually had me stumped, granted it is the first day. I am used to VI and making my way around the environment in bash.

1. Small is beautiful ~ do more with less ~ hardware doesn't need to be that strong to run Linux or UNIX mostly UNIX cause of the old computers only running on a few kb of ram
2. do one thing and do that one thing extremely well ~ example LS what does LS do it lists files extremely well ~ which is what it was designed to do. cant copy files or do anything other than what it was designed to d
3. everything is a file in a UNIX system ( only about 90% true ) UNIX introduced the concept of io streams or data streams

• This is important because it changes the way we think about the operating system as a whole.

1. Standard input STDIN
2. standard output STDOUT
3. standard error STDER

1. > redirect stdout and turn it into a write operation. write operation starts at the beginning of the file and writes on the next available lines
2. » redirect stdout and append the file with a write operation.
3. 2> redirect standard error Write
4. 2» redirect standard error append
5. < redirects standard input

• cat command can be used to view the contents of a file without opening the file itself
• concatenate = cat but was shortened due to the space that the word would take up in the os
• example:

lab46:~$ cat "myfilename" 

• would list the content of all the file

• CTRL+D mapped to the end of file character - END of file character or EOF character is the end of a file - some files will not exit until the EOF character is reached
• < ~ controls where the input comes from for example : having a file with the word SOS in it and then running the command morse, would result in the file providing the input to the command

lab46:~$ morse < "file name"

• CP ~ short for copy file creates a duplicate EXAMPLE ~ (cp thing stuff creates a copy of thing and names it stuff)
• MV ~ moves the file file is no longer where it was. moves file to same directory under different name if wished. UNIX does not have a rename command because of the redundancy in it
• RM ~ rm filename ( removes the file that is listed after RM) rm - i defaults with a prompt making sure that you want to delete the file ,can override with -f force, rm -rf deletes a directory even with stuff rf means recursive goes deeper until its all gone rm -rf * would delete all directories because * is a wildcard
• LN ~ creates shortcuts to files ln -s filename1 filename2 makes a shortcut of filename1 named filename2 and without -s makes it a semi replication
• ls -l ~ long list of things in directory
• diff ~ shows differences between files
• touch “filename” ~ makes a file

• Shortcuts and commands really make navigating UNIX a lot easier.
• A lot of this raises the question “ why should we do something when the computer can do it for us?”
• It also makes us ask “at what point do we stop doing the manual labor?”

• programming languages are lower level than the shell.
• lower the level the more control you can have over the details, but the more you have to do by hands.
• Higher level the less control you have but you have to do less

• pwn ~ shows the current directory that the user is in
• $USER ~ shows the current user that you are logged in with
• $ ~ stands for variable expansion does its best to show the contents of a variable
• Example :

• When you use the command LS, you get multiple colored results.
• These colors each represent a different type of file.
• The Defaults are as follows

1. blue - directory files
2. cyan - light blue - symbolic link
3. red - broken symbolic link - or - compressed files
4. magenta - bright purple - media files
5. green - executable file
6. yellow - special ( device ) file such as keyboard or mouse
7. white foreground and red background - set uid set gid file

• At the command prompt type

lab46:~$ pwd

• This shows us the current directory
• Next we should make a new sub-directory

lab46:~$ mkdir closet

• This makes the directory closet
• Move into the directory

lab46:~$ cd closet
lab46:~/closet$ 

• Type in pwd again, and the path listed would have been appended to your new location
• This leads into two types of paths

1. absolute path - contains the entire addresses
2. relative path - contains a character or shorter name to represent the path to location of file or user

• Next create a file named skeleton with the touch command

lab46:~/closet$ touch skeleton

• Using ls, there should now be a file named skeleton in the closet
• Next we will create a file named cake, but we will use echo to create the file and content

lab46:~/closet$ echo "ingredients" > cake

• This creates a file named cake with the word ingredients in it
• To add to the file without removing all content, we must replace > with » a

lab46:~/closet$ echo "diamond pickaxe" >> cake

• The file cake now has ingredients and a diamond pickaxe in it

• ls -l - lists all files
• la -la ~ addition of “a” includes hidden files in the listing of files
• every directory has a “.” and a “..” in it
• shift and \ is a | or a pipe character. it merges commands or settings together
• ls -l | less ~ lists the list in a paging format
• ls -l | more ~ lists the list without the ability to search or go up
• tty
• ldd ~ print dependencies
• mesg ~ using an n or a y toggles the settings for whether or not messages can be sent

1. Every file has permission settings
2. After an ls -la, you can see what type of file a file is, and who controls it

• The first position signify file type

1. - ordinary file
2. L - symbolic link
3. Bc - block and character
4. S - socket
5. p - pipe

• The second third and forth spot represents user permission and owner
• The fifth sixth and seventh spot represents the group the file belongs to
• The eighth ninth and tenth spot represent the permissions of the world, or global environment
• These are followed by

1. followed by name of owner
2. followed by group ownership

• Each permission setting has a special value

1. r ~ read - 4
2. w ~ write - 2
3. x ~ execute except for a directory that means its searchable - 1
4. - ~ no permission - 0
5. t ~ sticky bit add on for file permissions you can write but cant delete
6. s ~

• To change the values for a user or group, you use the command chmod chmod (value)(value)(value), value is an additive of read write and execute that maxes at 7

1. / ~ directory known as root directory
2. bin ~ directory means binary essential files for basic system usage
3. dev ~ directory for devices or special files
4. etc ~ system configuration files such as ldap ntp
5. lib ~ libraries such as the c library at libc.so.6
6. lib64 ~ links to lib directory
7. lib32 ~ separate 32bit layer library considered foreign
8. root ~ root users home directory
9. lost+found ~ recovered files from a disk rarely used only when there is a serious hardware problem
10. mnt ~ mount point for storage or media
11. media ~ same as mnt
12. opt ~ optional software or commercial vendors
13. proc ~ information on running processes ~ has a directory for every running process
14. sbin ~ essential tool for administrator
15. selinux ~ security Linux extension
16. sys ~ modern replacement of proc machine readable instead of user readable. easier for machine to reach
17. tmp ~ TEMP FILES
18. var ~ variety of things that fit nowhere else such as mail from lab 46
19. usr ~ provides usr useful stuff not critical for operation, place for text editors ~ local/bin contains mods

1. regular ordinary files ( text files mp3s movies)
2. directory files / link files (is a file that contains other files or reference other files)
3. special files

1. We learned a lot about how the subsystem in linux and unix works
2. Knowing what the default directories were, really helped to draw a parallel to the windows environment
3. With the lecture I was finally able to understand the meaning of chmod 777 that I use ever so much in my daily time. I know it is now read write and execute for all users. I feel silly for not knowing that.

• Every OS has a shell
• Some of the OSes have the same kind of shell
• Some of the OSes have a different shell
• It is good as a computer personal to familiarize with most of them

1. mac - finder
2. unix - bash sh tosh csh zsh rc fish ksh ~ change shell with chsh
3. windows - explorer

• Nesting is opening something within something that can be opened within that nearly indefinitely
• You can nest the shell bash many times over
• if you type bash in bash it becomes nested

-bash
       |_bash
                 |_bash
                           |_bash

• sub shells can inherit global variables
• if you type exit it takes you one level up

• In bash, the different style quotation marks can have different meaning in output

1. “ ~ half quite, allows variable expansion
2. ' ~ full quote, literal quote offering no expansion - gives back exactly what you typed
3. ` ~ back tick back-quote - allow command expansion

• Example

my example will not work in wiki syntax and crashes my opus upon saving

• This embeds the results of a command string right into the output syntax
• Knowing how to do these can really help with controlling output
• There are other special things you can use to manipulate the data output

1. \ “whack” - toggle special meaning of the following character ex \n newline \t tab
2. “date” gives back date

• There are also wildcards that can be used to give back specific lists

1. * means 0 or more of anything
2. ? means 1 of any character
3. [ ] character class put sequence of characters in it ~ matches all enclosed
4. [^ ] inverted character class ~ matches none enclosed

• Example

lab46:~$ ls ????

• lists only the four character commands
• This is important for when we are searching for a specific thing on the system

• Knowing how to control the output is an amazing ability, I Just think i will struggle with remembering which one does what
• I also know that after working with unix in cli, switching back to windows is going to be a challenge

Today we learned about VI

• VI / VIM - it does things extremely well. it is a good text editor
• ed - line editor edit your file a line at a time
• One of the first application of UNIX was a text editor for a secretary
• The need for a visual editor was what birthed VI
• Bill joy - created vi
• came up with the idea to allow every key on the keyboard to be a command
• Key can be used for commands and can be used for input. it has two commands
• 1: COMMAND MODE ~ what you start vi in
• 2: INPUT MODE → INSERT MODE
• A and M are common between the qwerty and other keyboard styles
• a and m both do things in both modes

• ESC takes you to command mode
• i ~ insert mode - while in insert mode, you can type
• h is left
• j is down
• k is up
• l is right
• w skips forward a word
• b skips back a word

these will even show up in the normal CLI with CTRL + value sometimes case of character changes command

• ^ snaps you to begining of current line horizontal
• $ is end of current line horizontal
• G is end line vertically
• x delete single character
• u undo for line
• X backspace
• d$
• d^
• dd - deletes entire line
• p pastes dd line below
• P pastes dd line above
• anything can be prefixed with a number to multiply the commands
• anything can be prefixed with the letter c pops you in place of where command was issued
• cc changes whole line
• I takes you to insert at begining on line
• a takes you insert after character
• A takes you insert end of line
• o inserts new line below current
• O iinserts new line above current
• u
• U
• yy copies without cutting
• / followed by something lets you search
• : extended command mode
• :.co+0 pastes at current location
• :.co4
• . MEANS CURRENT LINE
• .+2m$ current line plus next two lines move to end of file
• SOURCE COMMAND DESTINATION
• :w is save
• :q quit
• :wq save and quit
• :w filename saves as name
• ZZ will only save an exit if you saved
• :%s/e/EE/g
• :set tabstop=4
• syntax on
• syntax off
• set number
• set nonumber
• set cursor line
• vi ~/vimrc to edit vi

Its nice to have learned a few new VI commands I didnt know before

Today almost everything learned was pure bash la -a shows all hidden files

• .plan contains your plan
• finger (user name) - gives your output
• .signature your signature
• .bashrc
• PS1 changes your prompt appearance Example PS1='C:\\\w> ' makes it say C:\~>
• cd and a few characters and pressing tab will complete the directory name for you
• running old command !412
• ctrl + r searches for commands
• first line of shell script should always be the following
• #!/bin/bash - this is called a shbang
• bash scripting is basically executable pseudo code

We made two scripts

  1 #!/bin/bash
  2 #
  3 # script1.sh - my first script
  4 #
  5 echo -n "What is your name?"
  6 read name
  7 echo "Hi, ${name} how are you?"
  8 exit 0

This asks for your name and asks how you are and

  1 #!/bin/bash
  2 #
  3 # scipt2.sh - my second script
  4 #
  5 pick=$((RANDOM%91+1))
  6     echo -n " Pick a number :"
  7 read number
  8 if [ "$pick" -eq "$number" ]; then
  9     echo "you win"
 10 elif [ "$pick" -gt "$number" ]; then
 11     echo "$pick > $number you lose"
 12 else
 13     echo "$pick < $number you lose"
 14 fi
 15 exit 0

this one is a number game that has you guess a number

Today we learned about how processes work

• ctrl c generates a signal interrupt
• ctrl d is mapped to the end of file character
• end of file characters will exit a file
• you can log out of a terminal by doing ctrl d
• all your terminal session is, is an open file waiting for the end of file command to occur
• EOF - end of file
• The “kill” command will terminate a process
• man kill - lists all of the 64 kill commands you can use
• ctrl z pauses the process without actually stopping it
• when you type “jobs” it lists the processes stopped
• when you type sleep 3600& , it adds to the list of things in the jobs command

• multitasking - each login session that you have, you have a foreground and a background, running something at your prompt such as (vi) then vi is currently in the foreground
• the unix system is called a multi-user multi-tasking operating system
• some programs can be put and run in the background without using the foreground
• we are limited to one foreground per loin session
• we can put any number of things in the background granted that they don't require user interaction via a keyboard

1) stopped - in the background not doing anything, not working towards finis hing its process 2) running - means the job is running in the background perfectly fine

• Each job has a number that is personal to itself called a PID
• With the ps command, we can find out the PID number for something
• With the PID number we can send something into the background
• bg (job number) can move a thing to the background
• fg (job number) can move a thing to the foreground
• Some processes will not go into the background
• you can not be running cat in the background because it requires interaction , and it instantly goes back to stopped once the terminal is not focused on it
• screen the program that we are using for our irc server is actually tricking the system into having a multi-foreground environment
• daemon is something that you can run in the background that is launched from the terminal then happily running along in the background without needing a terminal to input any information, usually involved in web-servers
• daemons are also considered servers in the unix system
• daemons end with the letter d
• apache d more than likely the apache daemon
• all a server means is that it is handling a piece of software that can handle requests
• ctrl l refreshes your screen, and then you will only see what you put there cat is an actual program in our path that we can run
• when we run cat once, that program running is called a process
• a process is a program in action
• We can time a program to run
• Example

(sleep 30;ls)& runs ls after 30

Its nice seeing how processes work. I have dealt with daemons before, so I understand them well enough.

Today we learned mostly about the cat command but we also learned about a few other things

I am going to list it all out since it doesnt really group at all

• Regular Expressions - set of characters used to represent a pattern
• Basic Regular expression- not garrented to be universal
• . - match any single symbol
• * - 0 or more of the previous
• \< match start of word
• \> match end of word
• ^ - match start of line
• $ - match end of line
• [ ] = match one of enclosed
• [^ ] = do no match any of the enclosed
• ( ) =
• | = logical or

• cd /usr/share/dict/
• ls
• less words - lists all words

• cat words |grep '….'|wc -l replace …. with search parameters
• cat words |grep '^….$'|wc -l finds all 4 letter words
• cat words |grep '^.[aeiouyAEIOUY]..$'|wc -l - find second character vowel
• cat words |grep '…..e$'|wc -l - six or more ending in e
• cat words |grep '^……*e$'|wc -l - six or more ending in e
• cat words |grep '^[sS].*[mM].*[eE]$'|wc -l - word starting in S, ending in E, m in the middl
• cat words |grep '^.*[aeiouy][aeiouy].*$'|wc -l - two or mor
• cat words |egrep 'ed$|ing$' |wc -l - ends in ed or ing
• cat words |egrep '^pre|^pro|ly$' |wc -l - begins with pre or pro or ends in ly

its fun looking at the dictionary and playing with cat

• Loops
• For loops
• list for loops
• numeric based for loops
• we can type it on the cli

for ((i=0;i<10;i++));do
>  echo"$i"
>  done

• first part is the starting point
• second part is do as long as
• third part is how you get to the end
• the double parenthesis allow for multiple levels of arithmetic

• xte - part of a tools suite called xautomation
• With XTE we can create scripts that move the mouse, click, and do keystrokes
• Example

xte 'mousemove 0 0'
xte 'sleep 1'
xte 'mouseclick 1'
xte 'mousedown 1'
xte 'sleep 1'
xte 'mousemove 100 100'
xte 'sleep 1'
xte 'mouseup 1'
xte 'mousemove 300 250'
xte 'sleep 1'
xte 'mouseclick 1'

• This moves the mouse to xpaint and starts it
• Another example

      1 xte 'mousemove 0 0'
      2 xte 'sleep 1'
      3 xte 'mouseclick 1'
      4 xte 'mousedown 1'
      5 xte 'sleep 1'
      6 xte 'mousemove 100 100'
      7 xte 'sleep 1'
      8 xte 'mouseup 1'
      9 xte 'mousemove 300 250'
     10 xte 'sleep 1'
     11 xte 'mouseclick 1'
     12 xte 'sleep 1'
     13 xte 'mousemove 40 110'
     14 xte 'sleep 1'
     15 xte 'mouseclick 1'
     16 xte 'sleep 1'
     17 xte 'mousemove 40 130'
     18 xte 'mouseclick 1'
     19 xte 'sleep 1'
     20 xte 'mousemove 600 110'
     21 xte 'mouseclick 1'
     22 xte 'mousemove 200 200'
     23 xte 'mouseclick 1'
     24 xte 'mousedown 1'
     25 for ((x=200;x<500;x+=50));do
     26 y=200;
     27 xte "mousemove $x $y"
     28 xte "usleep 200000"
     29 done
     30 
     31 for ((y=200;y<500;y+=50));do
     32 x=500;
     33 xte "mousemove $x $y"
     34 xte "usleep 200000"
     35 done
     36 
     37 for ((x=500;x>190;x-=50));do
     38 y=500;
     39 xte "mousemove $x $y"
     40 xte "usleep 200000"
     41 done
     42 
     43 for ((y=500;y>190;y-=50));do
     44 x=200;
     45 xte "mousemove $x $y"
     46 xte "usleep 200000"
     47 done
     48 xte "mouseup 1"

• This opens and draws a square using xte

Xte is fun and I could see many good, and bad uses for it for torturing my clients

• Today we created a program that opens xpaint and draws something specific
• I chose to draw a battle scene from pokemon using xpaint
• so far I only have the frame drawn from the picture

      1 xte 'mousemove 200 200'
      2 xte 'mouseclick 1'
      3 xte 'mousedown 1'
      4 for ((x=200;x<360;x+=10));do
      5 y=200;
      6 xte "mousemove $x $y"
      7 xte "usleep 10000"
      8 done
      9 
     10 for ((y=200;y<344;y+=4));do
     11 x=360;
     12 xte "mousemove $x $y"
     13 xte "usleep 10000"
     14 done
     15 
     16 for ((x=360;x>200;x-=10));do
     17 y=344;
     18 xte "mousemove $x $y"
     19 xte "usleep 10000"
     20 done
     21 
     22 for ((y=344;y>196;y-=4));do
     23 x=200;
     24 xte "mousemove $x $y"
     25 xte "usleep 10000"
     26 done
     27 xte "mouseup 1"
     28 
     29 for ((x=350;x>209;x-=10));do
     30 y=340;
     31 xte "mousemove $x $y"
     32 xte "mousedown 1"
     33 xte "usleep 10000"
     34 done
     35 xte "mouseup 1"
     36 
     37 for ((x=350;x>209;x-=10));do
     38 y=339
     39 xte "mousemove $x $y"
     40 xte "mousedown 1"
     41 xte "usleep 10000"
     42 done
     43 xte "mouseup 1"
     44 
     45 for ((x=350;x>209;x-=10));do
     46 y=337
     47 xte "mousemove $x $y"
     48 xte "mousedown 1"
     49 xte "usleep 10000"

    50 done

     51 xte "mouseup 1"
     52 
     53 for ((y=335;y>302;y-=1));do
     54 x=211
     55 xte "mousemove $x $y"
     56 xte "mousedown 1"
     57 xte "usleep 10000"
     58 done
     59 xte "mouseup 1"
     60 
     61 for ((y=335;y>302;y-=1));do
     62 x=210
     63 xte "mousemove $x $y"
     64 xte "mousedown 1"
     65 xte "usleep 10000"
     66 done
     67 xte "mouseup 1"
     68 
     69 for ((y=335;y>302;y-=1));do
     70 x=208
     71 xte "mousemove $x $y"
     72 xte "mousedown 1"
     73 xte "usleep 10000"
     74 done
     75 xte "mouseup 1"
     76 
     77 for ((y=335;y>302;y-=1));do
     78 x=349
     79 xte "mousemove $x $y"
     80 xte "mousedown 1"
     81 xte "usleep 10000"
     82 done
     83 xte "mouseup 1"
     84 
     85 for ((y=335;y>302;y-=1));do
     86 x=350
     87 xte "mousemove $x $y"
     88 xte "mousedown 1"
     89 xte "usleep 10000"
     90 done
     91 xte "mouseup 1"
     92 
     93 for ((y=335;y>302;y-=1));do
     94 x=352
     95 xte "mousemove $x $y"
     96 xte "mousedown 1"
     97 xte "usleep 10000"
    98 done
     99 xte "mouseup 1"
    100 
    101 for ((x=350;x>209;x-=10));do
    102 y=300
    103 xte "mousemove $x $y"
    104 xte "mousedown 1"
    105 xte "usleep 10000"
    106 done
    107 
    108 for ((x=350;x>209;x-=10));do
    109 y=299
    110 xte "mousemove $x $y"
    111 xte "usleep 10000"
    112 done
    113 xte "mouseup 1"
    114 
    115 for ((x=342;x>268;x-=1));do
    116 y=290
    117 xte "mousemove $x $y"
    118 xte "mousedown 1"
    119 xte "usleep 10000"
    120 done
    121 xte "mouseup 1"
    122 
    123 for ((x=271;x<275;x+=1));do
    124 y=289
    125 xte "mousemove $x $y"
    126 xte "mousedown 1"
    127 xte "usleep 10000"
 128 done
    129 xte "mouseup 1"
    130 
    131 for ((x=273;x<275;x+=1));do
    132 y=288
    133 xte "mousemove $x $y"
    134 xte "mousedown 1"
    135 xte "usleep 10000"
    136 done
    137 xte "mouseup 1"
    138 
    139 for ((y=290;y>278;y-=1));do
    140 x=342
    141 xte "mousemove $x $y"
    142 xte "mousedown 1"
    143 xte "usleep 10000"
    144 done
    145 xte "mouseup 1"

• What if we only had one value that we could call with one subscript value
• they are commonly subscripted with the [ ] brackets
• some languages may start at one and some languages start at 0
• bash like c programming starts at z
• first value would be [0]
• second would be [1]
• third would be [2]
• you can have a common name to each value
• so
• name[0]
• name[1]
• name[2]

• we created a program to add pokemon exp together

for((i=0; i<12; i++)); do

    echo -n "Enter scores:"

    read score

    battleexp[$i]=$score

done
total=0
for((i=0; i<12;i++)); do

    let total = $total + ${battleexp[$i]}

done

    "Your total score is $total"

• count until you input -1

• differences between scripts and programs
• interperated - interperates each line as it goes
• html
• bash
• wbscript
• php
• python
• javascript
• compiled - everything is translated upfront so that the computer can understand it
• c
• c++
• pascal
• fortran
• bopl changed to b and that changed to c
• source code portability to make up for the inability to have things ready for all devices
• the compiled product can not be moved to the device but the source code can be compiled onto the new device
• ascii ebcdic
• hardware choices dwindled after the 90s
• cellphones and tablets brought back into competition the diversity
• with a c compiler you do not have to have any realization of differences just re compile
• low level - assembly and machine code
• high level - java c++ python
• the higher the level, the less you get to interact with the hardware
• in c you have # include <stdio.h>
• its a preproccessing directive
• its a step c goes through
• it does work before it processes the syntax
• grabs the file and takes it contents and dumps them right into our file
• c is terminated with a semi colon
• #include <stdio.h>
• int main ()
• {
• printf(“Hello World'\n”);
• return(0);
• }

This is all review from C programming

Today was a review day

Today was the knowledge assessment, it was fairly simple other than the last problem. The problem where we were asked to make the brute program work.

This week we worked on some bash scripts for checking if a directory exists

  1 #!/bin/bash
  2 #
  3 #
  4 #
  5 #
  6 #
  7 if [ -z "$1" ]; then
  8     echo -n "Enter a path: "
  9     read path
 10     chk=`ls $path 2>&1 | grep 'No such file'| wc -l`
 11     if [ "$chk" -eq 1 ]; then
 12     path=`pwd`
 13 fi
 14 else
 15     paths="$1"
 16 fi
 17 echo $path
 18 cd $path
 19     max=0
 20 for file in `ls -1d` * ; do
 21     c=`echo $file | wc -c`
 22     echo "c is $c"
 23     data[$c]=$((${data[$c]}+1))
 24     if [ "$max" -lt "$c" ]; then
 25         max=$c
 26     fi
 27 done
 28 for (( i=1; i<=$max; i++));do
 29         printf "%2d | " $i
 30     if [ -z "${data[$i]}" ]; then
 31         data[$i]=0
 32     fi
 33 for ((j=0;j<${data[$i]};j++)); do
 34     echo -n "*"
 35 done
 36 done

Today we created a script that would run a simple website using our UID as a port number

#/bin/bash
#
while true; do

    { echo -e 'HTTP/1.1 200 OK \r\n'; cat /etc/motd;} | nc -l 5836

done

We also learned about the different protocols on the internet and about error codes

Today we learned how to cat a file, but to organize the output in a readable manner, or however we want it to be organized some examples

cat file | grep "<th class="ddtitle'
sed stream editor
cat winter2014-20131025.html | grep '^<th class="ddtitle' | sed 's/^<th class="ddtitle.*crn_in=.....">//g' | sed 's/<\/a><\/th>//g'
cat winter2014-20131025.html | grep '^<th class="ddtitle' | sed 's/^<th class="ddtitle.*crn_in=.....">//g' | sed 's/<\/a><\/th>//g' | sed 's/^\(.*\) - \(.....\) - \(.*\) - \(...\)$/\2:\3-\4:\1/g'

This week we continued to work on cating the course list file.

We were given a small script to mess around with

ifs=; for line in `cat consolodate`; do 
crn=`echo $line | sed 's/^.* - \(.....\) - .....*$/\1/g'
 touch $crn
 echo $line >> $crm
 done

we learned about ifs internal field separator

we were also given

cat catstuff | enhance | enhance | ENHANCE > coursedata

1)

• From the archives/ subdirectory of the UNIX public directory (/var/public/unix/archives):
• a) Copy the archive1.tar.gz and archive2.zip files to your home directory.
• b) i did this with cp -r /var/public/unix/archives .

2)

• to open the files tar and zip files
• a) zip uses unzip command
• b) tar uses tar xvzf for tar.gz
• c) found the information in the man page
• 3) tar -cf arc.tar archives
• 4) gzip -9 tar
• 5) they are different
• a) zip compresses and organizes into a single file
• b) tar organizes into a single file and gzip compresses a single file
• things make more sense now

1.

• b the file seems to be a simple text file
• c when catting the file it seems to be a text file
• d the file is now a gzip compressed file
• e the file is now a max compression file

2.

• it doesnt appear to be a text file
• the file is actually a tar file
• cp unix.text /var/public/unix/file/submit/$USER-file.txt && echo “Success”
• cat unix.text | mail -s ”[CS: FILE]“ wedge@lab46.corning-cc.edu $USER

• The people that talked to me are aforce2 lwall1
• Jkosty has messages disabled. Write write you have write permissions turned off
• Waiting for a connection. Can join peoples invites
• Aforce2 and lwall1
• You can open a shell using esc

1

• http://lab46.corning-cc.edu/~jkosty6/cs.html

2

• http://lab46.corning-cc.edu/~jkosty6/ex0.html

• personal website i made from what i learned here
• https://kostyhome.remotewebaccess.com/homepage/

1

• BLOCK DEVICES
• xvda1
• xvda2
• xvda3
• character devices
• vcs
• vcs1
• vcsa

2

• a first xen virtual disk
• b nfs:/home
• c second xen virtual disk
• f xen virtual disks

3

• /dev/pts/38
• /dev/pts/49

4

• both are allowed to message

5

• it changes the plux to a minus
• it changes the permission on the terminal

6

• everything is a file so we can cat the message of the day and view it as if it was a text file because that is exactly what it is

7

• i typed cat /dev/null
• it is a blank which may be useful for when we want our output or input to be nothing at all

1

• B it is in /usr/include/

2

• A char = 8 bits
• B 255 unique states
• C range is -32768 to 32767
• D short int is 4
• E 0 to 4294967295
• F 32
• G 32

3

• C gcc -o dtypes dtypes.c

4

• A 4294967295
• B yea it was the max value for unsigned int
• C -1 is the value
• D I did because signed can go negative
• 6 the result is the before number being the max and the after being the least
• It does make sense since the range is -32768 to 32767. It rolls over to the lowest value after adding one to the maximum value

  1 #include <stdio.h>
  2
  3 int main()
  4 {
  5     unsigned int a, x;
   6     signed short int b, y;
  7
  8     a = 0; // zero not letter "O"
  9     b = 32767;
 10     x = a - 1;
 11     y = b + 1;
 12
 13     printf("signed short int before: %hd \t after: %hd\n", b, y);
 14
 15     return(0);
 16 }

B cat pelopwar.txt | grep coast | wc –l causes 9 matches

• We can copy from source to destination using dd command
• Doing this created a near duplicate file.
• The permissions are different
• The owner is different
• The size is the same
• The output is identical

We can compare files line by line using the diff command md5sum(1): computes an MD5 hash of a file's contents, creating a unique data fingerprint

• Originally developed by Bell Labs
• From the 1970s
• Many companies are switching to a UNIX system to save money
• Many large and important fields ( Such as Space Exploration ) use UNIX

• Unix is case sensitive
• Example ~ each is a different command

1. Word
2. word
3. wOrD
4. wOrd

• User names on UNIX are normally lower case
• passwords contain any number of combinations of letters, numbers, and symbols

• I use putty to connect to our school stuff

• I simply type in the lab46.corning-cc.edu on port 22 and click open.
• At the prompt

login as :

• Enter your lab 46 user name

password : 

• Enter your lab 46 password
• Because I have logged in before, I get no password change prompt

• Every system has a message of the day
• Ours looks like this

 __         _     _ _   __   . . . . . . . . . . . . . . . . . . . . . . . . .
|  |   __ _| |__ / | |_/ /   . Basic System Usage:  Type 'usage' at prompt   .
|  |__/ _` | '_ \\_  _/ _ \  . Events and News:     Type 'news' at prompt    .
|_____\__,_|_.__/  |_|\___/  . Broken E-mail?       Type 'fixmail' at prompt .
---------------------------  . Check Lab46 Mail:    Type 'alpine' at prompt  .
c o r n i n g - c c . e d u  . . . . . . . . . . . . . . . . . . . . . . . . .

 Lab46 is the Computer & Information Science Department's Student Development
 Server for Computer-related coursework, projects, and exploration.  For more
 information, please check out:
  .. .  .    .        .                .                .        .    .  . ..
 .  Lab46 Web Page:       http://lab46.corning-cc.edu/                       .
 .  Lab46 Help Form:      http://lab46.corning-cc.edu/help_request           .
 .  Help E-mail:          haas@corning-cc.edu or wedge@lab46.corning-cc.edu  .
  .. .  .    .        .                .                .        .    .  . ..

• The file shown in the MOTD is in the /etc/motd text file.

• The default directory prompt is ”~“
• This symbol actually represents a real directory on the system
• Using the PWD command we get ( with my log on )

lab46:~$ pwd
/home/jkosty6

• This means my default path is /home/jkosty6

• Navigating around a UNIX system only requires knowledge of the command CD
• If I wanted to move to my src folder I would type

lab46:~$ cd src

• The directory prompt would change to

lab46:~/src$

• and PWD would change to

lab46:~/src$ pwd
/home/jkosty6/src

• we can also go back down a level using cd ..

lab46:~/src$ cd ..
lab46:~$

• we can use the cd .. command to leave our home directory as well

lab46:~$ cd ..
lab46:/home$

• In UNIX there is a command to list everything in a directory ls
• If I type LS in my main directory I get

lab46:~$ ls
Desktop    Downloads  Music     Public     Videos  bin     hw           src
Documents  Maildir    Pictures  Templates  a.out   closet  public_html

• The command to create directory is mkdir
• If I wanted to make a directory called temp, I would type

lab46:~$ mkdir temp

• If I wanted to make a directory called bin, I would type

lab46:~$ mkdir bin

• If I wanted to remove a directory called temp, I would type

lab46:~$ rmdir temp

• You can see who is on the system by typing

lab46:~$ who

• This lists out all active logons
• You can message any of the people online, but only as long as they have a + next to their name
• To turn off messages you type

lab46:~$ mesg n

• This turns your + into a -

• Our system uses a mail setup called alpine
• To get into alpine we type

lab46:~$ alpine

• We should get a screen like this

  ALPINE 2.00   MAIN MENU               Folder: INBOX                1 Message +


          ?     HELP               -  Get help using Alpine

          C     COMPOSE MESSAGE    -  Compose and send a message

          I     MESSAGE INDEX      -  View messages in current folder

          L     FOLDER LIST        -  Select a folder to view

          A     ADDRESS BOOK       -  Update address book

          S     SETUP              -  Configure Alpine Options

          Q     QUIT               -  Leave the Alpine program




                  Copyright 2006-2008 University of Washington

? Help                     P PrevCmd                 R RelNotes
O OTHER CMDS > [Index]     N NextCmd                 K KBLock

• To Check our email we press I and enter , this takes us to our index
• To send an email we press C and enter , and fill in the needed information

• Our class has a mailing list
• It can be subscribed to at http://lab46.corning-cc.edu/mailman/listinfo/unix
• Find the UNIX options and subscribe
• Ones subscribed a test email can be sent to the mailing list at the address unix@lab46.corning-cc.edu
• I sent one with the subject “Testing” and the body “testing, please ignore”
• It worked as seen here

• Everything is a file.
• Small is beautiful.
• Do one thing, and do that one thing extremely well.

• root user / superuser:

1. Strongest account on the system
2. Typically used by the system admin
3. has no restrictions imposed on it or protections

• base (or root) of home directory:

1. The starting part in a subtree of a file system
2. on lab 46 it is our folder

• blocks:

1. Units of data on a filesystem
2. Normally in 512 or 1024 byte blocks
3. CDs use 2048 byte blocks
4. Rare hardware sometimes uses its own blocks

• kilobytes:

1. 1024 bytes
2. Sometimes refereed to as a KiB
3. Binary representation often shows it as being 1000bytes
4. This is often the case with hard drive manufacturers who see their hard drives with 1000 multiples instead of 1024

• multi-user:

1. Means the system can handle multiple users at once
2. These users can do their own commands
3. Unix is this type of system

• multi-tasking:

1. Means a system can handle multiple tasks
2. Means a system can handle multiple users running multiple different tasks at the same time

• MUA:

1. acronym for “Mail User Agent
2. Mail client
3. Allows the user to send or receive email

• mailing list:

1. A gathering of email addresses used to create a discussion forum
2. allows for centralized announcements relayed to people

• post/posting:

1. a message sent to a mailing list is called a post
2. When you send a message yourself its called posting

• command-line:

1. any string of characters that manipulate features after being typed in a prompt

• You can log off the lab by typing “logout”
• You could also just type “exit”
• or you could ctrl + D

• Unix as a whole is a collection of many useful tools

• Most commands in UNIX have an English equivalent

1. list is ls
2. copy is cp
3. move is mv
4. remove is rm
5. link is ln

• Unix has a command to list things called ls
• When you type “ls”, you get a list of all the files or directories inside of your current directory
• These files can be colored differently to reflect what type of file they are
• The “ls” command can have additional arguments added to it to help narrow down your results
• for example ls -l would result in something like this

lab46:~$ ls -l
-rw-r--r-- 1 jkosty6 lab46   440 Sep 13 10:15 2.00   MAIN MENU               Folder: INBOX                1 Message +
drwxr-xr-x 2 jkosty6 lab46     6 Aug 28 12:20 Desktop
drwxr-xr-x 2 jkosty6 lab46    20 Aug 29 15:28 Documents
drwxr-xr-x 2 jkosty6 lab46     6 Aug 28 12:20 Downloads
lrwxrwxrwx 1 jkosty6 lab46    17 Aug 25 11:56 Maildir -> /var/mail/jkosty6
drwxr-xr-x 2 jkosty6 lab46     6 Aug 28 12:20 Music
drwxr-xr-x 2 jkosty6 lab46     6 Aug 28 12:20 Pictures
drwxr-xr-x 2 jkosty6 lab46     6 Aug 28 12:20 Public
drwxr-xr-x 2 jkosty6 lab46     6 Aug 28 12:20 Templates
drwxr-xr-x 2 jkosty6 lab46     6 Aug 28 12:20 Videos
-rwxr-xr-x 1 jkosty6 lab46  6561 Aug 29 16:34 a.out
drwxr-xr-x 2 jkosty6 lab46     6 Sep  3 08:57 bin
drwxr-xr-x 3 jkosty6 lab46    46 Sep  4 15:37 closet
-rwxr-xr-x 1 jkosty6 lab46 16638 Aug 29 16:42 hw
drwx-----x 2 jkosty6 lab46     6 Aug 26  2009 public_html
drwx------ 6 jkosty6 lab46    83 Sep 13 16:35 src
lab46:~$

• Adding -l makes it list everything but also list all permission values and ownership information
• This can be used to find out the size of files
• For example if we wanted to find out the size of the grep file in bin we would get a result like this

-rwxr-xr-x 1 root root  119288 Apr 21  2010 grep

• This shows us that it is 119288 in size
• We can also use this to get a time stamp on a file
• If we used this to look at cat for example

-rwxr-xr-x 1 root root   52288 Apr 28  2010 cat

• It has a timestamp of april 28th

• If we wanted to copy something we would use the “cp” command
• If we wanted to change to our home directory we would type just “cd”
• To copy a file into our working directory we would type

lab46:~$ cp (directory and file name of target)

• To make a duplicate inside of the same directory you would type

lab46:~$ cp (original copy name SPACE duplicate name)

• To move a file we use the mv command
• and example would be

lab46:~$ mv (file name) (directory destination)

• This can also be used to rename files

lab46:~$ mv (old file name) (new file name)

• This means that UNIX doesn't have a stand alone rename program, since renaming is really just moving a file into a new file

• To remove things you use the rm command
• example would be

lab46:~$ rm (filename)

• You need to confirm the deletion in order for the file to be removed

• In UNIX you can create a shortcut to a file by using the ln command

lab46:~$ ln [-s] (target file) (shortcut file)

• The -s makes the file be a soft file, meaning that it isnt the same exact size as the original, otherwise this would create a linked identical file

• UNIX contains manuals about most, if not all of its programs within itself
• These can be easily accessed using the command “man” followed by the command you wish to inquire about
• You can also skip to a specific section by adding in a section number before or after the command in question
• Once a manual is open, you can navigate it using the arrow keys, and you can quit using q

• Unix handles its file system much differently than what we are used to with windows
• Its filesystem is broken up into many parts
• The parts are kind of easy to figure out what they stand for

1. / - Root, the lowest you can go on a system, it is the base or foundation for the entire OS
2. bin - Essential basic tools for normal system usage
3. etc - the systems configuration files
4. home - directory location of the system user files
5. lib, lib64, lib32 - system libraries very important and can be different depending on the architecture of your system
6. mnt - place where file systems get mounted such as hard drives
7. root - the administrator or super users folder
8. sbin - necessary system admin utilities
9. tmp - Temporary directory
10. usr - Additional (secondary) system functionality & userspace tools
11. var - Misc. items that have no place such as mail

• If we wanted to change to the root directory, we would do

lab46:~$ cd /
lab46:/$

• The result of an ls from this directory would list out all the above, and possibly more

lab46:/$ ls
bin   etc         lib    lost+found  opt   sbin     sys  var
boot  home        lib32  media       proc  selinux  tmp  vmlinuz
dev   initrd.img  lib64  mnt         root  srv      usr
lab46:/$

• of all of these directories, some of them can not be accessed
• root folder is one of them, unless you are root

• To get back to your home directory you type just cd
• you could manually get back to your home directory by typing (specific to my username)

lab46:/home$ cd /
lab46:/$ cd home
lab46:/home$ cd jkosty6
lab46:~$

• As stated before, the current directory you are in is the working directory
• It can be reached by typing in the “pwd” command

• There are two types of path names

1. Absolute - The exact location in the file system - the pwd command returns this
2. Relative - The exact location on the file system is unknown and only comparable to the specific location

• There are hidden files referenced when you list all with ls -a
• These files are .. and .
• Every directory has these
• .. refers to the previous directory
• . refers to the current directory
• These can be used as relative pathnames comparable to your current working directory
• You can change directory using them such as cd .. would move you to the lower directory

• On UNIX everything is a file
• Even hardware is a file
• There are three types of files

1. Regular Files - Text and executable files
2. Directories - A file that points to other files
3. Special Files - Devices and network specific items

• These files all have permissions for 3 user groups

1. user - the owner of the file
2. group - the group that owns a file
3. other - everyone else

• These groups are limited or allowed to

1. read
2. write
3. execute

• These can be added in any combination to any file
• Each of these permissions caries a value

1. read 4 r view / read the file
2. write 2 w save / create / modify / delete the file
3. execute / search 1 x run / parse through contents of a file

• You add together the values you want in order to reflect what you want
• example 421 would make a user have read, group have write, global have execute, - 777 would be all 3 for all 3

• Cat means - concatenate files and print on the standard output
• Cat can be used for both input and output
• examples

lab46:~$ cd /etc
lab46:/etc$ cat motd
 __         _     _ _   __   . . . . . . . . . . . . . . . . . . . . . . . . .
|  |   __ _| |__ / | |_/ /   . Basic System Usage:  Type 'usage' at prompt   .
|  |__/ _` | '_ \\_  _/ _ \  . Events and News:     Type 'news' at prompt    .
|_____\__,_|_.__/  |_|\___/  . Broken E-mail?       Type 'fixmail' at prompt .
---------------------------  . Check Lab46 Mail:    Type 'alpine' at prompt  .
c o r n i n g - c c . e d u  . . . . . . . . . . . . . . . . . . . . . . . . .

 Lab46 is the Computer & Information Science Department's Student Development
 Server for Computer-related coursework, projects, and exploration.  For more
 information, please check out:
  .. .  .    .        .                .                .        .    .  . ..
 .  Lab46 Web Page:       http://lab46.corning-cc.edu/                       .
 .  Lab46 Help Form:      http://lab46.corning-cc.edu/help_request           .
 .  Help E-mail:          haas@corning-cc.edu or wedge@lab46.corning-cc.edu  .
  .. .  .    .        .                .                .        .    .  . ..

• If we put in the wrong command, we can cancel cat with ctrl c

• wc(1) utility can be used for counting how many lines (as well as characters and words) are present in a text file.

lab46:/etc$ wc passwd
  27   32 1135 passwd

• We can display the linecount by adding -l

lab46:/etc$ wc -l passwd
27 passwd

• This shows there are 27 lines
• There is the “head” command
• This command shows how ever many lines you specify
• with head -n –lines=16, we could display the first 16 lines of something
• The tail command lets us show the last lines of a file
• If we use tail -f, we can monitor a file
• we could use this to monitor lists and modifications

• i - insert before cursor
• o - insert line below
• O - insert line above
• a - insert after cursor
• :wq - save and exit
• :w - save the file
• :q! - quit without saving
• ZZ - quit and save only if changed
• h (or left arrow) - move cursor left
• j (or down arrow) - move cursor down
• k (or up arrow) - move cursor up
• l (or right arrow) - move cursor right

• The means for interacting with hardware is an operating system.
• In unix there are multiple parts

1. Kernel - the core of the OS. It handles everything- manages I/O, etc.
2. Drivers - components that instruct the kernel how to function or deal with a piece of hardware.
3. Userspace - non-kernel level. System applications, utilities, files. Users exist here, hence the name “user space”

• At this level there are multiple servers running
• these servers are called daemons
• users of the system have access via a shell
• shell, or command interpreter (or command processor)
• ITs responsible for

1. interactive use
2. customization
3. programming

• The shell can be customized
• These were called personal configuration files

• special control characters exist that possess special powers

Control Code 	System Code 	Description
CTRL-C 	INTR 	interrupt
CTRL-D 	EOF 	issue end of file character
CTRL-G 		sound bell
CTRL-H 	BS 	send backspace
CTRL-J 	LF 	send linefeed
CTRL-L 		refresh screen
CTRL-M 	CR 	send carriage return
CTRL-Q 	XON 	start code*
CTRL-S 	XOFF 	stop code*
CTRL-V 		escape the following character
CTRL-Z 	SUSPEND 	suspend current job
CTRL-[ 	ESC 	send escape character 

In unix there are hidden files called dotfiles, and used on login or for configuration purposes

dotfile 	description
.bash_profile 	The first personal initialization file bash searches
.bashrc 	Session personalization file called by .bash_profile
.cshrc   	A personal initialization file for the csh/tcsh shells
.exrc 	        A configuration file for vi/ex
.signature 	Text file containing a signature banner for e-mail
.plan 	        A personal banner file that is displayed on finger(1) lookups
.forward 	A file used in automatic e-mail forwarding
.pinerc 	A configuration file for pine
.vimrc  	A configuration file for vim 

• with ls -a we can see the files . and .. and many others
• WIth vi we can changes our .signature file to do many things

  1 I see pokemon
  2 John Kosty
  3 C / C++ and UNIX

• is what mine was changed to

• These modifiy the terminal in some way

1. $PATH
2. $HOSTNAME
3. $USER
4. $TERM
5. $SHELL

• printenv utility list yours environment variables
• You can create aliases using the alias command
• You can remove aliases with unalias command
• alias nameofalias=“utility -options –options”

• you can view your history with the history command
• ! makes you do something special with history
• !history_number you will run the command represented by the number

• tab completions can complete commands and pathnames for you
• all you do is hit tab

Its nice review on how to use the command line's more unique features

• Wildcards are a shorthand
• allow for you to do actions based on commonality

Symbol 	Description
* 	match 0 or more characters
? 	match exactly one character
[ ] 	character class - match any of the enclosed characters.
[^ ] 	inverted character class - do not match any of the enclosed characters.

• The terminal sends and receives data by three means
• Standard Input (stdin), Standard Output (stdout), and Standard Error (stderr)
• The shell has a was of using these

Symbol 	Description
> 	STDOUT redirection operator
>> 	STDOUT append redirection operator
< 	STDIN redirection operator
2> 	STDERR redirection operator
2>> 	STDERR append redirection operator
| 	pipe 

• Pagers are programs created to handle the output of something
• They can also be used to limit the output so that reading is easier
• Page by page
• line by line
• The commands more or less are pagers

• The different quotes have their place in unix

Symbol 	Name 	Description
` 	backquote 	                command expansion
' 	single (or full) quote 	        literal quote, no expansion
" 	double (or partial) quote 	variable expansion 

===Conclusions===
Nice review from C

We were told to make a script with this inside of it

ls ~
df
who

if we try to run it using (dot slash) it will say we lack the permission.

1. We can view the permissions on the file by doing ls -la script1.sh
2. The owner has read and write. The user has read. Global has read
3. We can use chmod to change the permissions on the file to what we would like
4. chmod 777 script1.sh
5. The script works

Anything that you can type on the command line can be added to the script

There are two easy ways to do IO

• Echo - echo “phrase to echo” ~ -n gets rid of newline after command
• Read - read variable ~ variable is anything we define. can call it with $variable
• let - enables simple mathematical functions - lab46:~$ let num1=$num1+$num2

echo "What is your birth year?"
read birth
currentday=$(date | awk ' {print $6}')
let output=$currentday-$birth
echo $output

• A shabang in a script can ensure that a specific environment is ran when running a script
• We do this with #!/path/to/shell -options or in bash #!/bin/bash

• Often times we have to compare things with our scripts
• If statements are one of the options
• The sample code gives the user a prompt for input twice and stores the data

#!/bin/bash
 
echo -n "Pick a number: "
read num1
 
echo -n "Pick another number: "
read num2

• This code can be further modified using an if statement

if [ "$num1" -lt "$num2" ]; then
    echo "$num2 is greater than $num1"
fi

• If we want more than one arguement to our if statement then we
• need to use else if statements or elif

if [ "$num1" -lt "$num2" ]; then
    echo "$num2 is greater than $num1"
elif [ "$num2" -lt "$num1" ]; then
    echo "$num1 is greater than $num2"
fi

• We can use one else statement in our script

if [ "$num1" -lt "$num2" ]; then
    echo "$num2 is greater than $num1"
elif [ "$num2" -lt "$num1" ]; then
    echo "$num1 is greater than $num2"
else
    echo "$num1 and $num2 are equal in value"
fi

* we can make a program that asks for a number and generates a random number to guess against.

#!/bin/bash
pick=$(($RANDOM % 20))
echo "Pick a number between 1 and 20"
end=4
counter=0
while [ "$counter" -lt "4" ]; do
read picked
    if [ "$pick" -eq "$picked" ]; then
        echo "$picked is the number!"
        exit
    elif [ "$pick" -lt "$picked" ]; then
        echo "$picked is greater than the number!"
        let counter=counter+1
    elif [ "$pick" -gt "$picked" ]; then
        echo "$picked is less than the number!"
        let counter=counter+1
    fi
done

• When dealing with loops we have numeric for loops
• They have a

1. Starting condition
2. a loop until condition
3. and a method to get there

#!/bin/bash

for((i=1; i<=10; i++)); do
    printf "$i "
done

prints the provided script without newline

#!/bin/bash

for((i=20; i>=2; i--)); do
    printf "$i "
done

steps backwards from 20 to 2

in the provided list based for loop

The loop goes 8 times The fifth time through the color is blue

echo -n "First color is: "
for color in red orange yellow green blue indigo violet; do
if [ "$color" == "indigo" ]; then
    echo "$color"
    echo -n "The last color is: "
elif [ "$color" == "violet" ]; then
    echo "$color"
    exit
else
    echo "$color"
    echo -n "Next color is: "
fi
done

is my modified code

echo "Give me a number"
read number
echo $number > file$number

the code to create file with number

#!/bin/bash
printf "Please enterdirector to process: "
read directory
printf "Processing ...\n\n"
echo "Directory: $directory"
cd "$directory"
filecount=$(ls -la | wc -l)
if [ "$filecount" -gt "60" ]; then
    filecount=60
fi
echo "Total Files: $filecount"

* We learned about multitasking * we can see the running processes with PS command * this works with

lab46:~$ ps
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
jkosty6  11177  0.4  0.1  13644  2004 pts/24   SNs  23:20   0:00 -bash
jkosty6  11206  8.0  0.0   8588   988 pts/24   RN+  23:23   0:00 ps u

* we can see our processes in other shells using the same

ps -e lists all processes on the system

using & you can instruct a command to run in the background The count file is a C file You can determine this with the file command gcc -o count count.c ./count

output is

real 0m36.795s user 0m35.482s sys 0m0.608s

adding an & to it runs it in the background

We can use the semicolon as a command seperator to so that once the first command is done the second one executes

sleep 8 ; ls /var > multitask.lab.txt &

you cant log out cause tasks are stopped this might be incase you dont want to terminate the jobs you can keep running them

the links job is number 2

bringing it to foreground caused error

moving it back to background worked

fg 1 foregrounded cat

cat is gone all jobs gone

We can kill processes using kill 8 kill -l a 1 b 34 c 9 d 2

jkosty6 + pts/55 2013-12-12 15:35 . 3574 (cpe-69-204-219-21.stny.res.rr.com) jkosty6 + pts/82 2013-12-12 11:25 . 24306 (cpe-69-204-219-21.stny.res.rr.com)

dev/pts/82 dev/pts/55

kill -9 24369

killed pts/82

no messages at all just closed putty

no longer logged in twice

ps -e | grep statd the PID of init is 1 root own cron 1190 is pid cron is a task scheduler

We can compile a file with gcc -o output input.c

g++ -o output input.cc We can compile with this

to assemble an assembly file we can do as -o outpout.o input.s to run it on the system we need to do ld -o binary object.o

copied over the files compiled them with

as -o helloASM.o helloASM.S ld -o helloASM helloASM.o

gcc -o helloC helloC.c

g++ -o helloCPP helloCPP.cc

If we run it without a ./ it will fail to run saying command not found with ./ it executes it from the current directory, so it works

helloC.c is a ASCII C Program Text file helloASM.S is a ASCII assembler program test file helloCPP.cc is a ASCII C++ Program text file

if we compile with gcc -S helloC.c it turns it into assembly and an assembly file when we cat or VI the file we can see that it is pure assembly

if we type as -o hello.o helloC.s it creates an ELF 64bit LSB relocatable x86-64 sysv not stripped it seems to have been turned into an object form of the S file

You can run make files to deal with multiple source files that need compiling at once

We can use the grep command to narrow down our results in files cat /etc/passwd | grep System would limit it to only lines with system

• using my ititials for searching I would get

lab46:~$ cat /etc/passwd | grep '^[jpk]' proxy:x:13:13:proxy:/bin:/bin/sh

• Replacing all parts with correct parts

cat regex.html | sed 's/<centre>/<center>/g' | sed 's/<\/CENTRE>/<\/center>/g' | sed 's/<b>/<strong>/g' | sed 's/<\/b>/<\/strong>/g'

• Words

cd /etc/dictionaries-common/ found it using ls -la and looking at the link seems to be just a text file with all the words 98569 words and you get it with cat words | wc -l

• regex

1. 5 character length cat words | grep “^…..$”
2. all words starting with jpk cat words | grep “^[JPKjpk]”
3. first begining middle middle last last cat words | grep “^[jJ].*[pP].*[kK]$”
4. begin and end with vowel cat words | grep “^[aeiouy].*[aeiouy]$”
5. begin initial vowel second est last cat words | grep “^[jJpPkK][aeiouy].*[est]$”
6. dont start with initial cat words | grep “^[^jJpPkK]”
7. all 3 letter words ending in e cat words | egrep '^..[e]$'
8. contain bob not ending in b cat words | grep 'bob.*[^b]$'
9. all words starting with blue cat words | grep '^blue'
10. contains no vowels cat words | grep '^[^aeiouyAEIOUY]*$'
11. dont begin vowel. second letter anything. third abcd ends in vowel cat words | grep '^[^aeiouyAEIOUY].[abcd]*[aeiouyAEIOUY]$'

• We copy the file with

cp /var/public/unix/courselist/fall2011-20110417.html.gz .

• The file size is

72355

• file type

gzip compressed file

• open it with

gunzip fall2011-20110417.html.gz

• File size uncompressed

2427432

• Compression ratio is

98%

• Searching for a course

you use the slash then search parameter

• Compare data

most of them have the same filler junk around them

• To isolate only classes

cat fall2011-20110417.html | grep crn

• does it snap with /

yes it does

• consistant with n

yes

cat fall2011-20110417.html | grep crn | sed 's/<th class="ddtitle" scope="colgroup"><a href="https:\/\/.*crn_in=.....">//g'

• how many courses next semester

cat fall2011-20110417.html | grep crn | sed 's/<th class="ddtitle" scope="colgroup"><a href="https:\/\/.*crn_in=.....">//g' | sed 's/<\/a>.*$//g' | awk '{print $1}' | uniq | wc -l 348

Today the lab was about filters. * We can get the Standard output of a file by catting it * We can pipe the file with wc -l to count the lines in the file

* We can filter out all lines in a file by piping it with grep “keyword” * we can filter out all lines in a file by piping it twice to see if both lines contain something cat “filename” | grep “keyword” | grep “keyword”

To find students that are freshmen

• cat sample.db | grep Freshmen
• cat simple.db | sort | grep Freshman
• cat simple.db | uniq | sort | grep Freshman
• cat simple.db | uniq | sort | grep Freshman | wc -l

• We can use the cut command to cut columns out of output
• echo “hello there:this:is:a:bunch of:text.” | cut -d”:“ -f3 displays is

lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f1,6
hello there:text.

• displays what was asked, but I cant figure out how to cut the :

• We can search and replace parts of a string using the sed command
• Using sed, we can fix our cut output to eliminate the :
• to change everything from t to T

lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f1,6 | sed -e 's/:/ /g' | sed -e 's/t/T/g'

"hello there:this:is:a:bunch of:text." | cut -d":" -f1,6 | sed -e 's/:/ /g' | sed -e 's/\./\*/g'

• would replace every period with an astrix

• we can use the head command to print from top to bottom a specific ammount of lines
• we can use the tail command to print from bottom to top a specific ammount of lines

• ===Line Endings===
• In dos we have carriage return line feed
• Mac we have carriage return
• Unix we have line feed

• Show unique students in database
• cat sample.db | sort | cut -d”:“ -f1 | uniq | head -n -1

• show unique majors
• cat sample.db | cut -d”:“ -f3 | sort | uniq | head -n -1

• unique candies
• cat sample.db | cut -d”:“ -f5 | sort | uniq | head -n -1 | sed -e '

• first 22 lines
• cat pelopwar.txt | head -22

• last 4 lines
• cat pelopwar.txt | tail -4

• 32-48
• cat pelopwar.txt | head -48 | tail -16

• last 12 lines first 4
• cat pelopwar.txt | tail -12 | head -4