BASH/C2/Introduction-to-BASH-Shell-Scripting/English

Title of script: Introduction to BASH shell scripting

Author: FOSSEE and Spoken-tutorial Team

Keywords: video tutorial, Bash shell, hello world, execute a script

Visual Cue	Narration
Display Slide	Dear friends, welcome to the spoken tutorial on Introduction to BASH shell scripting.
Display Slide Learning Objectives	In this tutorial, we will learn About different types of Shells To write a Bash Shell script and To execute it.
Display Slide Prerequisites www.spoken-tutorial.org	To follow this tutorial you should be familiar with Linux Operating System If not, then for relevant Linux tutorials, please visit our website.
Display slide	For this tutorial I am using Ubuntu Linux 12.04 OS and GNU Bash version 4.1.10. GNU bash version 4 or above is recommended to practice this tutorial.
Display slide Bash Shell	Let us see what a Bash Shell is. Bash Shell is a Command language interpreter, that executes commands. These commands are read from the standard input device. The input device can be your keyboard or a simple text file.
	Let me show you what is a Bash Shell.
Press Ctrl+Alt+T	Open the terminal by pressing Ctrl+Alt+T keys simultaneously . This will open the 'Gnome-terminal'.
On the Terminal, type - echo $SHELL Press Enter	To check which type of shell we are using, type: echo space dollar sign SHELL('shell' in capital) Press Enter.
Highlight /bin/bash	You will see the output printed on the next line as: slash bin slash bash This indicates that we are using the Bash Shell.
Display Slide Different Types of Shells Bourne Shell- /bin/sh	Let us know different types of Shells available Bourne Shell- /bin/sh == This was original UNIX shell written by Stephen Bourne. == It lacked interactivity provided by most modern shells today
C Shell- /bin/csh	C Shell- /bin/csh It provides features lacking in Bourne Shell
K Shell- /bin/ksh	K Shell- /bin/ksh It was created by David Korn It has features of both B Shell and C Shell, along with some additional features.
Bash Shell- /bin/bash	Bash Shell- /bin/bash The Bash Shell was developed by GNU Project It is based on B Shell language. It has features of C and K Shells.
Display Slide TC Shell- /bin/tcsh	TC Shell- /bin/tcsh It is the default Shell of FreeBSD and its descendants.
Z Shell- /bin/zsh	Z shell- /bin/zsh It is a Shell designed for interactive use. It has many useful features of bash, ksh, and tcsh.
Display Slide Bash Shell script	Now let us see what a Bash Shell script is. The Bash Shell script contains a series of Bash commands in plain text file. tells the Shell to execute this text file, instead of typing the commands.
	Let us see how to write a simple Bash script. Let us test the echo command, which will print Hello World on the terminal.
Switch to the terminal >> type echo “Hello World” Press Enter	Let's go to the terminal and type: echo space open double quotes Hello space world close double quotes and press Enter.
Output: Hello World	This prints Hello World on the terminal.
	The command worked as expected.
Highlight echo “Hello World”	Now, what if we want to use this command in a file?
	Just put this command in a file and execute that file.
	So, let us write a simple “hello world” script.
	We will use gedit text-editor for this purpose. You are free to use your favourite text-editor.
Switch to the terminal >> type cd Desktop >> press Enter	I want to create my file on the Desktop. So, go back to the terminal and type: cd space Desktop Press Enter.
Type gedit hello_world.sh >> press Enter	Now type gedit space hello underscore world dot sh and press Enter.
Point to the header of the gedit window	We have opened a new file named hello_world.sh using gedit.
Type #!/bin/bash >> press Enter	In this file, type hash exclamation slash bin slash bash and press Enter.
Highlight this line	This is the first line of every bash script. It is called shebang or bang line.
Type # my first Bash script >> press Enter	Now, let's add a comment to the file by typing: hash my space first space Bash space script Press Enter.
Highlight #	Remember that any line after hash, is treated as a comment. And comments are ignored by the Bash interpreter.
Type echo “Hello World” >> press Enter	Now we can add the command which we used earlier. So type: echo space open double quotes Hello space world close double quotes and press Enter.
Type echo $SHELL >>Press Enter	Also in the next line, type: echo space dollar sign SHELL And press Enter.
Type echo `date` >> Press Enter	Then type: echo space backtick date backtick backtick symbol is present on the key which has tilde character. Now, press Enter.
Press CTRL+S	Press CTRL+S to save this file. We will close this file using ALT+F4.
Switch to the terminal	Now, let's go back to the terminal and make this file executable.
Type chmod +x hello_world.sh >> press Enter	So, type chmod space plus x space hello underscore world dot sh and press Enter.
Type ./ hello_world.sh >> press Enter	Now execute this file by typing dot slash hello underscore world dot sh Press Enter.
Output: Hello World	You can see Hello World displayed on the terminal.
Output: /bin/bash	The shell type is displayed on the next line. ie slash bin slash bash
Output: Wed May 8 15:59:36 IST 2013	We can see that Day, Month, Time, Time zone and Year are displayed. The output may vary depending on the system.
Display Slide	Summary In this tutorial we have learnt about Different types of Shells The Bash Shell and The Bash Shell script We also wrote a simple Shell script and executed it.
Display Slide Assignment	Write a simple Bash shell script to display the message - “Welcome to Bash learning” and “***************” on separate lines.
Display Slide Acknowledgement Slide	Watch the video available at the following link It summarises the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it
Display Slide Spoken Tutorial Workshops	The Spoken Tutorial Project Team Conducts workshops using spoken tutorials Gives certificates to those who pass an online test For more details, please write to contact@spoken-tutorial.org
Display Slide Acknowledgement	Spoken Tutorial Project is a part of the Talk to a Teacher project It is supported by the National Mission on Education through ICT, MHRD, Government of India More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro
	The script for this tutorial was written by the FOSSEE and Spoken Tutorial Teams, IIT Bombay. And this is Ashwini Patil from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Ashwini