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Why we choose UNIXWhy we choose UNIX Powerful

Multi-user operating system Good programming tools

• Most heavy-duty database management systems started out on Unix

Flexible   Thousands of tools that can be combined and recombined.

Reliable Unix is hard to crash.

     

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How to Access a UNIX MachineHow to Access a UNIX Machine

Your personal computer

(client)

rain.cise.ufl.edu

(server)

telnet / ftp

telnet: allows you to connect to other computers and use softwares thereftp: allows you to retrieve files from other computers.

     

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TelnetTelnet TELetype NETwork

A network protocol used on the Internet / LAN

By extension, refers to the program which provides the client part of the protocol

Once connected Log on as a regular user with access to

• application / software• data

A Telnet command request looks like this telnet rain.cise.ufl.edu

     

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FTPFTP File Transfer Protocol

A network protocol used on the Internet / LAN Allow to transfer files to and from remote computers

A ftp command request looks like this ftp rain.cise.ufl.edu

     

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SSHSSH Why SSH

Figures from http://www.suso.org/docs/shell/ssh.sdf

Download SSH http://www.openssh.org/

     

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More about SSHMore about SSH Recommendation for Windows

Putty as telnet tool• http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

WinSCP as ftp tool• http://winscp.net/eng/download.php

Other choices ftp, telnet using command line in windows Other softwares

• Core FTP

http://www.coreftp.com/download.html

     

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Unix CommandsUnix Commands man – manual (man gcc) ls – list directory contents (ls) pwd – prints working directory (pwd) cd – change directory (cd <subdirectory>) mkdir – create directory (mkdir <new directory> rm – remove a file (rm <file to remove>)

Use –r if removing a directory

     

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Unix Commands(cont)Unix Commands(cont) cp–copy a file (cp <source><destination>)

Use –r if copying a directory mv–move or rename files (mv <source> <destination>) jpico – text editor (jpico <file to edit>) gcc – compiler (gcc sourceFile.c)

-o option Directory shortcuts

~ home directory .. parent directory . sub directory

     

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Your First ProgramYour First Program#include <stdio.h>

int main()

{

printf("Hello World\n");

return 0;

}

Preprocessor: interact with input/output of your computer

You will see this at the beginning of nearly all programs

Tells computer to load file named <stdio.h>

<stdio.h> allows standard input/output operations

     

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Your First ProgramYour First Program#include <stdio.h>

int main()

{

printf("Hello World\n");

return 0;

}

Start point of the program

Preprocessor: interact with input/output of your computer

C programs contain one or more functions, exactly one of which must be main

int means that the function main will "return" an integer value

     

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Your First ProgramYour First Program#include <stdio.h>

int main()

{

printf("Hello World\n");

return 0;

}

Start point of the program

Preprocessor: interact with input/output of your computer

Start and finish of function

     

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Your First ProgramYour First Program#include <stdio.h>

int main()

{

printf("Hello World\n");

return 0;

} Printing a line of Text

Start point of the program

Preprocessor: interact with input/output of your computer

Start and finish of function

     

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Your First ProgramYour First Program#include <stdio.h>

int main()

{

printf("Hello World\n");

return 0;

} Printing a line of Text

Start point of the program

Preprocessor: interact with input/output of your computer

Start and finish of function

New line character

     

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Your First ProgramYour First Program#include <stdio.h>

int main()

{

printf("Hello World\n");

return 0;

} Printing a line of Text

Start point of the program

Preprocessor: interact with input/output of your computer

Start and finish of function

Finish and return value 0

A way to exit a function

It means that the program terminated normally in this case

     

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Comments for programsComments for programs Why need comments

Good habit Readable to others Remind yourself

How to comment /* … */ // …

Effects on compiler Examples

     

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CompilerCompiler What is compiler

A computer program (or set of programs) that translates text written in a computer language ( the source code) into another computer language (most time the executable file)

Why we need a compiler Available C compiler in UNIX system: gcc

gcc sourcefile.c –o exefile.exe

     

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Text EditorsText Editors Edit your code Using wordpad, or some text editor on

your personal computer Need to transfer your program to UNIX machine using ftp

Edit your code in UNIX using vi pico (jpico) emacs

     

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ProcedureProcedure

This is your C program. Type the code in any standard text editor, and save it as helloworld.c. Transfer it to rain.cise.ufl.edu if necessary

#include <stdio.h> int main() { printf("Hello World\n"); return 0; }

helloworld.c

C-compilerType gcc helloworld.c –o helloworld.exe

to compile helloworld.c into helloworld.exe using the gcc compiler

0011 0000 1010 01101100 0110 1011 01011010 1110 0110 1110

helloworld.exe The gcc compiler generates corresponding executable code named helloworld.exe. The computer can execute this machine readable code if you type ./helloworld.exe