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

Time

Narration

00:01

Dear friends, welcome to the Spoken tutorial on Introduction to BASH shell scripting.

00:08

In this tutorial, we will learn

00:10

* About different types of Shells

00:13

* To write a Bash Shell script and

00:16

* To execute it.

00:18

To follow this tutorial you should be familiar with Linux Operating System

00:25

If not, then for relevant Linux tutorials, please visit our website which is as shown.

00:32

For this tutorial I am using

00:35

* Ubuntu Linux 12.04 OS and

00:39

* GNU Bash version 4.1.10.

00:43

Please note GNU bash version 4 or above is recommended for practice.

00:50

Let us start with an Introduction

00:53

We will see what a Bash Shell is.

00:56

* Bash Shell is a Command language interpreter, that executes commands.

01:02

* These commands are read from the standard input device.

01:07

* The input device can be

01:09

*your keyboard

01:11

* or a simple text file.

01:14

Let me show you what is a Bash Shell.

01:16

Open the terminal window by pressing Ctrl+Alt+T keys simultaneously on your keyboard .

01:24

This will open the Gnome terminal.

01:27

To check which type of shell we are using, Type echo space dollar sign SHELL (In capital)

01:38

Press Enter.

01:40

You will see the output printed on the next line as slash bin slash bash

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This indicates that we are using the Bash Shell.

01:51

Now Let us know different types of Shells available

01:56

Let us switch back to our slides Bourne Shell

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* This was original UNIX shell written by Stephen Bourne.

02:06

* It lacked interactivity provided by most modern shells today

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C Shell

02:12

It provides features lacking in Bourne Shell

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K Shell

02:17

It was created by David Korn

02:20

It has features of both, B Shell and C Shell, along with some additional features.

02:27

Bash Shell

02:30

* The Bash Shell was developed by GNU Project

-

02:32

* It is based on B Shell language.

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* It has features of C and K Shells.

02:40

TC Shell

02:41

* It is the default Shell of FreeBSD and its descendants.

02:46

Z shell

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* It is a Shell designed for interactive use.

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* It has many useful features of ksh,bash and tcsh.

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Now let us see what a Bash Shell script is.

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The Bash Shell script contains a series of Bash commands in plain text file.

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* It tells the Shell to execute this text file, instead of typing the commands.

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Let us see how to write a simple Bash script.

03:20

We will test the echo command, which will print Hello World on the terminal.

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Go back to the terminal

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Now type echo space within double quotes Hello world

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and press Enter.

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This prints Hello World on the terminal.

03:40

The command worked as expected.

03:43

Now, what if we want to use this command in a file?

03:47

Just put this command in a file and execute that file.

03:52

I will use gedit text-editor for this purpose.

03:57

You are free to use your favourite text-editor.

04:00

I want to create my file on the Desktop.

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So, type cd space Desktop

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Press Enter.

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Now type gedit space hello underscore world dot sh space &'(ampersand sign)

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Gedit is the text editor. Hello underscore world dot sh is the file name and

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we use the & (ampersand) to free up the prompt.

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Now press Enter.

04:33

We have opened a new file named hello_world.sh using gedit.

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Now, type hash exclamation mark front slash bin front slash bash

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This is the first line of every bash script.

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It is called as shebang or bang line.

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Press Enter

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Now, let's add a comment to the file by typing

05:00

hash space my first Bash script

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Remember that any line after hash, is treated as a comment.

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And comments are ignored by the Bash interpreter.

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Now we can add the command which we used earlier.

05:19

Press Enter

05:20

and type echo space within double quotes Hello world

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press Enter.

05:28

Type echo space dollar sign SHELL (In Capital)

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press Enter.

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Type echo space backtick date backtick

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backtick symbol is present on the key which has tilde character.

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Now, click on Save to save the file.

05:50

Let us execute come back to our terminal

05:55

First we have to make the file executable.

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For this type chmod space plus x space hello underscore world dot sh

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and press Enter.

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Now Type

06:14

dot slash hello underscore world dot sh

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Press Enter.

06:22

You can see Hello World is displayed on the terminal.

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The shell type is displayed on the next line. ie slash bin slash bash

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And Day, Month, Time, Time zone and Year are displayed.

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The output may vary depending on the system.

06:43

Let us go back to our slide and summarize

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In this tutorial we have learnt about

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* Different types of Shells

06:50

* Bash Shell

06:51

*Bash Shell script

06:52

To write a simple Shell script and to execute the script.

06:57

As an assignment Write a simple script to display the message - * “Welcome to Bash learning”

07:03

* and “***************” (asterisks) on separate lines.

07:06

Watch the video available at the link shown below

07:10

It summarises the Spoken Tutorial project

07:13

If you do not have good bandwidth, you can download and watch it

07:17

The Spoken Tutorial Project Team

07:20

Conducts workshops using spoken tutorials

07:22

Gives certificates to those who pass an online test

07:26

For more details, please write to contact@spoken-tutorial.org

07:34

Spoken Tutorial Project is a part of the Talk to a Teacher project

07:39

It is supported by the National Mission on Education through ICT, MHRD, Government of India

07:45

More information on this Mission is available at the link shown below http://spoken tutorial.org\NMEICT-Intro

07:51

The script has been contributed by FOSSEE and Spoken Tutorial Teams, IIT Bombay.

This is Ashwini Patil from IIT Bombay signing off. Thank you for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14