DCN 3013: Network Programming

1
DCN 3013 Network Programming

• Chapter 1 Introduction
• by
• Muhammed Ramiza Ramli
• KUKTEM

2
Overview

• Introduction to Linux Programming
• Writing first C code in Linux
• Using vi editor
• Using Gnu Common Compiler (gcc) in command prompt
• Source Code
• Object Code
• Loadable modules/Binary file
• Integrated Development environment Anjuta

3
Linux Environment

• Linux Desktop

4
Linux Terminal
5
Linux Command

• ls - list a file/dir
• ls, ls -a, ls -l, ls -s
• rm ltfilegt - remove a file
• rm, rm -Rf
• cp ltsourcegt ltdistgt - copy a file
• mv ltsourcegt ltdistgt- move/rename a file
• mkdir - create a dir
• rmdir - remove a dir
• cd ltdistdirgt - change dir into dist dir
• and a lots more commands and variations of them

6
Output
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vi Editor

• most commonly used editor in Linux is vi
• can be invoked in terminal as below
• Syntax vi ltfilenamegt
• vi hello.c

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vi Editor

• vi have two input mode
• command mode
• edit mode
• Command mode were used for
• save, search word, replace character , etc
• can be switch to by pressing Esc button
• Edit mode were used to insert or edit data into
  file.
• can be switch to by pressing several key
• a append
• i insert

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vi command

• in command mode, we can switch to edit mode to
  start writing by pressing i or a
• to go to the certain location, we can move the
  cursor by
• h left, j up, k down, and l right
• to save a file we must be in command mode and
  using command w
• w - write
• q - quit
• wq - write and quit
• q! - quit without save
• w file1 - write as file1

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vi command

• Once in edit mode, we can start writing.
• to save the file switch to command mode by
  pressing Esc.
• In command mode we can directly go to certain
  line by typing
• ltlinenumbergt
• 5 ltentergt
• To locate a key word typing
• /keyword
• cursor will be automatically set on word keyword

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Exercise

• open a new file
• vi hello.c
• Once started, vi will be put under command mode
• type i or a to enter the edit mode
• Write a simple C source program that will display
  Hello World in the screen.
• Switch to command mode to save it
• press Esc
• wq
• Finish

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Simple Program

• include ltstdio.hgt
• int main()?
• printf(Hello World!\n)
• return 0

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gcc

• every program written in Linux can be compiled
  by using gcc command
• gcc syntax
• gcc ltsourcegt -o ltoutputgt
• gcc hello.c -o hello
• invoking gcc without specifying the output file
• gcc ltsourcegt
• will produced an output as a.out
• To produces an object code file.o
• gcc -c ltsourcegt

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Run a program

• Program written in a source form
• file with .c
• It can be compiled into an object code
• file with .o
• Object code or several object code then can be
  linked in loadable modules or binary file
• by default a.out
• any name given by the user
• To run a program type the program name in the
  command prompt prefix with ./
• ./program

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Sample output
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Using IDE

• There are two Integrated Development
  Environment commonly used in Linux.
• Kdevelop Anjuta