Difference between revisions of "BASH/C2/Introduction-to-BASH-Shell-Scripting/English-timed"

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

|In this tutorial, we will learn  

|* About different types of '''Shells'''

|* To write a '''Bash Shell script''' and

|* To execute it.

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

| For this tutorial I am using  

|* '''Ubuntu Linux 12.04''' OS and  

|* '''GNU Bash''' version '''4.1.10'''.

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

| Let us start with an Introduction

|* '''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'''.

| Open the '''terminal''' window by pressing '''Ctrl+Alt+T''' keys simultaneously on your keyboard .

|  

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

|  

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

| Now Let us know different types of  '''Shells '''available   

|Let us switch back to our slides Bourne Shell

|* This was original UNIX shell written by Stephen Bourne.

|* It lacked interactivity provided by most modern shells today

| '''C Shell'''

 

|-

|It provides features lacking in '''Bourne Shell '''

| '''K Shell'''

 

|-

| It was created by David Korn

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

| '''Bash Shell'''

|* The '''Bash Shell '''was developed by '''GNU Project'''

| -

|* It is based on '''B Shell''' language.

|* It has features of''' C''' and '''K Shells.'''

| '''TC Shell'''

 

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

| '''Z shell'''  

|* It is a '''Shell''' designed for interactive use.  

|  

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

|  

|  

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

|  

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

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

|Go back to the '''terminal'''

|  

|Now type '''echo''' space within double quotes '''Hello  world'''

| The command worked as expected.

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

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

| I will use '''gedit''' text-editor for this purpose.  

| You are free to use your favourite text-editor.

| So, type '''cd''' space '''Desktop'''

|  

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

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

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

| Now press '''Enter.'''

 

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

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

| This is the first line of every bash script.

|Press '''Enter'''

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

|'''hash space my first Bash script'''

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

|And '''comments''' are ignored by the '''Bash '''interpreter.

| Now we can add the command which we used earlier.

|Press Enter

 

| and type '''echo''' space within double quotes '''Hello world'''

| press '''Enter'''.

 

|Type '''echo space dollar sign SHELL''' (In Capital)

| press '''Enter.'''

 

| Type '''echo space backtick date backtick'''

|Let us execute come back to our '''terminal'''

| First we have to  make the file executable.

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

| Now Type

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

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

|The output may vary depending on the system.

| Let us go back to our slide and summarize

|In this tutorial we have learnt about

|* Different types of '''Shells'''

|*  '''Bash Shell '''

 

|*'''Bash Shell script'''

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

| As an assignment Write a simple '''script''' to display the message -

  * “'''Welcome to Bash learning'''”

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

| Watch the video available at the link shown below

|It summarises the Spoken Tutorial project  

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

|The Spoken Tutorial Project Team

|Conducts workshops using spoken tutorials  

|Gives certificates to those who pass an online test  

|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 the link shown below http://spoken   tutorial.org\NMEICT-Intro

|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.