BASH/C2/Conditional-Loops/English-timed - Revision history

Pratik kamble at 10:54, 23 March 2017

2017-03-23T10:54:59Z

Sandhya.np14 at 11:42, 13 July 2015

2015-07-13T11:42:45Z

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Sandhya.np14 at 12:56, 3 July 2015

2015-07-03T12:56:13Z

Sandhya.np14 at 12:54, 3 July 2015

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PoojaMoolya at 06:41, 8 December 2014

2014-12-08T06:41:49Z

PoojaMoolya at 06:07, 8 December 2014

2014-12-08T06:07:04Z

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Ranjana: Created page with "'''Title of script:''' '''Basic If loop in BASH ''' '''Author:''' Ashwini Patil '''Keywords: video tutorial, for loop, while loop''' {| border=1 !Time !Narration |- | 00:0..."

2014-11-21T09:51:14Z

Created page with "'''Title of script:''' '''Basic If loop in BASH ''' '''Author:''' Ashwini Patil '''Keywords: video tutorial, for loop, while loop''' {| border=1 !Time !Narration |- | 00:0..."

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'''Title of script:''' '''Basic If loop in BASH '''
'''Author:''' Ashwini Patil
'''Keywords: video tutorial, for loop, while loop'''

{| border=1
!Time
!Narration
|-
| 00:01
| Dear friends, welcome to the spoken tutorial on '''loops''' in '''BASH'''.

|-
| 00:07
| In this tutorial, we will learn

|-
| 00:09
| * '''for loop'''

|-
| 00:11
| * '''while loop'''<br/> with a few examples
|-
| 00:15
| To record this tutorial I am using,

|-
| 00:18
| * '''Ubuntu Linux''' 12.04 '''Operating System '''

|-
| 00:22
| * '''GNU BASH''' version 4.1.10

|-
| 00:26
| Please note,'''GNU bash''' version '''4''' or above is recommended to practice this tutorial.

|-
| 00:34
| Let us start with an introduction to ''' loops'''

|-
| 00:37
| '''Loops''' are used to execute a group of statements repeatedly.

|-
| 00:43
| Let us see the syntax.

|-
| 00:45
| '''for expression 1, 2, 3'''

|-
| 00:49
| '''statement 1, 2, 3'''

|-
| 00:51
| And this is the end of '''for loop'''.

|-
| 00:55
| An alternate syntax of '''for loop '''is:

|-
| 00:58
| '''for variable in sequence/range'''

|-
| 01:03
| '''statement 1, 2, 3'''

|-
| 01:06
| And end of '''for loop'''.

|-
| 01:09
| Let us see an example of '''for loop''' using the first syntax.

|-
| 01:14
| In this program, we will calculate the sum of first '''n''' numbers.
|-
| 01: 20
| Note that our filename is '''for.sh'''

|-
| 01: 25
| This is our '''shebang line'''.

|-
| 01: 28
| The variable '''number''' will store the value given by user.

|-
| 01: 34
| The value is an integer here.

|-
| 01: 37
| Now, we initialize the variable '''sum''' as zero.

|-
| 01: 42
| This is where we begin the '''for loop.'''

|-
| 01: 45
| First, we initialize '''i''' to '''1'''.

|-
| 01: 48
| Then we check whether '''i''' is less than or equal to '''number'''.

|-
| 01: 54
| Now here, we calculate the '''sum''' as '''sum plus I'''.

|-
| 02: 00
| and then we print it.

|-
| 02: 03
| After this, we increment the value of '''i''' by '''1'''.

|-
| 02: 08
| And then we check the condition till this condition is '''false'''.
|-
| 02: 14
| On exiting the '''for loop,''' this message is printed.

|-
| 02: 19
| Let us execute the program and observe what happens.

|-
| 02: 24
| On the '''terminal''' type - '''chmod +x for.sh'''

|-
| 02: 31
| Then type: '''./for.sh'''

|-
| 02: 36
| I will enter '''5''' as the input number.

|-
| 02: 40
| The '''sum''' that is calculated for each value of '''I''' is displayed.

|-
| 02: 46
| After that, the last line of the output is displayed:

|-
| 02: 50
| '''Sum of first n numbers is 15'''

|-
| 02: 54
| Now let us see the flow of the program.

|-
| 02: 57
| Let me resize the windows.

|-
| 03: 00
| First we have value of '''i''' as '''1'''.

|-
| 03: 04
| Then we check whether ''' 1 ''' is less than or equal to ''' 5.'''

|-
| 03: 10
| Since the condition is '''true,''' we calculate '''sum''' as ''' 0 + 1.'''

|-
| 03: 16
| Now we have '''sum '''as '''1.'''

|-
| 03: 20
| Then we print '''sum ''' i.e '''1.'''

|-
| 03: 24
| Next, '''I''' is incremented by '''1''' and the new value of ''' i ''' is ''' 2.'''

|-
| 03: 31
| Then we check whether ''' 2 ''' is less than or equal to ''' 5.'''

|-
| 03: 36
| The condition is '''true''' and now sum will be ''' 1 + 2 ''' i.e ''' 3.'''

|-
| 03: 44
| '''i ''' is then incremented by '''1''' and then the new value of ''' i''' is ''' 3.'''

|-
| 03: 51
| And we get '''sum''' as ''' 6.'''

|-
| 03: 55
| The script will continue to add the next value of ''' I ''' to the previous value in ''' sum.'''

|-
| 04: 02
| This will continue till '''<nowiki>i<=5</nowiki> is false.'''

|-
| 04: 09
| On exiting the '''for loop,''' the final message is printed.

|-
| 04: 14
| Let us see another example of '''for loop'''using the second syntax.

|-
| 04: 20
| I have written the code in this file and named it as '''for-loop.sh'''

|-
| 04: 27
| This simple program will list the files in a directory.

|-
| 04: 32
| This is the '''shebang line.'''

|-
| 04: 35
| Then we have '''for loop'''.

|-
| 04: 37
| '''ls''' command lists the directory content.

|-
| 04: 41
| '''-1 (hyphen one)''' lists one file per line.

|-
| 04: 46
| This will list all the files present in your home directory.

|-
| 04: 51
| This is the end of '''for loop.'''

|-
| 04: 53
| Let us execute the script on the '''terminal''' by typing -

|-
| 04: 58
| '''chmod +x for-loop.sh'''

|-
| 05: 04
| '''./for-loop.sh'''

|-
| 05: 09
| This will display all the files present in the '''Home''' directory.

|-
| 05: 14
| Now, we will learn about ''' while loop.'''

|-
| 05: 18
| Let us understand the syntax first.

|-
| 05: 21
| '''while condition'''
'''statement 1, 2, 3'''
End of '''while loop'''.

|-
| 05: 27
| This means that the '''while loop''' will execute as long as the condition is '''true.'''

|-
| 05: 34
| Let us see an example of '''while loop.'''

|-
| 05: 37
| Here I have named it as '''while.sh'''

|-
| 05: 42
| In this program, we will calculate the sum of even numbers within a given range.

|-
| 05: 49
| Let us go through the code.

|-
| 05: 52
| Here, we accept a number from the user and store it in variable '''number'''.

|-
| 05: 59
| Next, we declare variables '''i''' and '''sum''' and initialize them to ''' 0 (zero).'''

|-
| 06: 06
| Now this is the '''while condition.'''

|-
| 06: 08
| Here we check whether '''i''' is '''less than or equal''' to value of '''number''' given by the user.

|-
| 06:17
| Then we calculate the '''sum''' by adding value of '''i''' to value of '''sum'''.

|-
| 06:24
| Next, we increment the value of '''i''' with '''2'''.

|-
| 06: 28
| This will ensure that we only add the even numbers.

|-
| 06: 33
| And the while loop is repeated till the value of '''i''' exceeds the value of '''number.'''
|-
| 06: 40
| When we exit the '''while loop, '''we print the sum of all the even numbers within the given range.

|-
| 06:47
| Let us execute the program.

|-
| 06:50
| Type on the '''terminal''':

|-
| 06:52
| '''chmod +x while.sh'''

|-
| 06:56
| '''./while.sh'''

|-
| 07:00
| I will give '''15''' as my input.

|-
| 07:04
| The last line of the output is:

|-
| 07:06
| '''Sum of even numbers within the given range is 56.'''

|-
| 07:11
| Let me resize the window and explain the output.

|-
| 07:14
| First we check whether '''i''' which is '''0,''' is less than or equal to the '''number''', which is '''15'''.

|-
| 07:24
| The condition is '''true,''' hence '''sum''' will be '''0+0''' I.e '''0.'''

|-
| 07:31
| Now '''i''' will be incremented by '''2''' and the '''new''' value of ''' i ''' is ''' 2.'''

|-
| 07:37
| Then we check if '''2''' is less than or equal to '''15'''.

|-
| 07:43
| The condition again is '''true;''' so we add '''0+2.'''

|-
| 07:49
| Now '''sum ''' has the value '''2.'''

|-
| 07:52
| Again the value of '''i''' will be incremented by '''2'''.

|-
| 07:56
| So now value of '''i''' will be '''2+2''' I.e '''4.'''

|-
| 08:03
| And the next value of ''' sum ''' will be '''4+2''' I.e '''6.'''

|-
| 08:09
| In the same way, the script will continue to add '''2''' to the previous value of '''i, '''till it exceeds '''15'''.

|-
| 08:18
| And we get the total value in '''sum''' as ''' 56.'''

|-
| 08:24
| This brings us to the end of this tutorial.

|-
| 08:27
| Let us summarize

|-
| 08:28
| In this tutorial we learnt two different syntax of '''for loop ''' and we also learnt about the '''while loop.'''

|-
| 08:37
| As an assignment -

|-
| 08:38
| Find the sum of the first "n" prime numbers.

|-
| 08:43
| Watch the video available at the link shown below

|-
| 08:46
| It summarises the Spoken Tutorial project

|-
| 08:50
| If you do not have good bandwidth, you can download and watch it

|-
| 08:54
| The Spoken Tutorial Project Team

|-
| 08:56
| Conducts workshops using spoken tutorials

|-
| 09:00
| Gives certificates to those who pass an online test

|-
| 09:04
| For more details, please write to contact@spoken-tutorial.org

|-
| 09:11
| Spoken Tutorial Project is a part of the Talk to a Teacher project

|-
| 09:14
| It is supported by the National Mission on Education through ICT, MHRD, Government of India

|-
| 09:22
| More information on this Mission is available at the link shown below.

|-
| 09:28
| The script has been contributed by Fossee and spoken-tutorial team.

|-
| 09:34
| This is Ashwini Patil from IIT Bombay signning off.

|-
| 09:38
| Thank You for joining.

|}

@@ Line 1: / Line 1: @@
 {| border=1
-!Time
+|'''Time'''
-!Narration
+|'''Narration'''
 |-
 | 00:01
@@ Line 16: / Line 12: @@
 |-
 | 00:09
-| * '''for loop'''
+|'''for loop'''
 |-
 | 00:11
-| * '''while loop'''<br/> with a few examples.
+|'''while loop'''<br/> with a few examples.
 |-
 | 00:15
@@ Line 27: / Line 23: @@
 |-
 | 00:18
-| * '''Ubuntu Linux''' 12.04 '''Operating System '''
+|'''Ubuntu Linux''' 12.04 '''Operating System '''
 |-
 | 00:22
-| * '''GNU BASH''' version 4.1.10
+|'''GNU BASH''' version 4.1.10
 |-
@@ Line 426: / Line 422: @@
 |-
 | 08:27
-| Let us summarize.
+| Let us summarize. In this tutorial, we learned two different syntax of '''for loop ''' and we also learned about the '''while loop.'''
-−
-|-
-| 08:28
-| In this tutorial, we learned two different syntax of '''for loop ''' and we also learned about the '''while loop.'''
 |-
 | 08:37
-|   As an assignment -
+| As an assignment -find the sum of the first "n" prime numbers.
-−
-|-
-| 08:38
-| find the sum of the first "n" prime numbers.
 |-
@@ Line 458: / Line 446: @@
 |-
 | 08:56
-|* Conducts workshops using spoken tutorials.
+|Conducts workshops using spoken tutorials.
 |-
 | 09:00
-|* Gives certificates to those who pass an online test.
+|Gives certificates to those who pass an online test.
 |-
@@ Line 469: / Line 457: @@
 |-
-|  09:11
+|09:11
-|  '''Spoken Tutorial''' Project is a part of the '''Talk to a Teacher''' project.
+|'''Spoken Tutorial''' Project is a part of the '''Talk to a Teacher''' project.
 |-
-|  09:14
+| 09:14
 | It is supported by the National Mission on Education through ICT, MHRD, Government of India.

@@ Line 372: / Line 372: @@
 | '''Sum of even numbers within the given range is 56.'''
-|  07:11
+|-
 |  Let me resize the window and explain the '''output'''.

@@ Line 118: / Line 118: @@
 |-
 | 01:54
-|  Now here, we calculate the '''sum''' as '''sum plus I'''.
+|  Now here, we calculate the '''sum''' as '''sum plus i'''.
 |-
@@ Line 153: / Line 153: @@
 |-
 |  02:40
-| The '''sum''' that is calculated for each value of '''I''' is displayed.
+| The '''sum''' that is calculated for each value of '''i''' is displayed.
 |-
@@ Line 193: / Line 193: @@
 |-
 |  03:24
-|  Next, '''I''' is incremented by '''1''' and the new value of ''' i ''' is ''' 2.'''
+|  Next, '''i''' is incremented by '''1''' and the new value of ''' i ''' is ''' 2.'''
 |-
@@ Line 213: / Line 213: @@
 |-
 | 03:55
-|  The script will continue to add the next value of ''' I ''' to the previous value in ''' sum.'''
+|  The script will continue to add the next value of ''' i ''' to the previous value in ''' sum.'''
 |-
 | 04:02
-| This will continue till '''<nowiki>i<=5</nowiki> is false.'''
+| This will continue till '''<nowiki>i<=5</nowiki>''' is '''false.'''
 |-
@@ Line 306: / Line 306: @@
 |-
-|05: 49
+|05:49
-|   Let us go through the code.
+| Let us go through the code.
 |-
@@ Line 372: / Line 372: @@
 | '''Sum of even numbers within the given range is 56.'''
-|-
+|---[[User:PoojaMoolya|PoojaMoolya]] ([[User talk:PoojaMoolya|talk]]) 12:11, 8 December 2014 (IST)
 |  07:11
 |  Let me resize the window and explain the output.
@@ Line 382: / Line 382: @@
 |-
 |  07:24
-|  The condition is '''true,''' hence '''sum''' will be '''0+0''' I.e '''0.'''
+|  The condition is '''true,''' hence '''sum''' will be '''0+0''' i.e '''0.'''
 |-
@@ Line 406: / Line 406: @@
 |-
 |  07:56
-| So now value of '''i''' will be '''2+2''' I.e '''4.'''
+| So now value of '''i''' will be '''2+2''' i.e '''4.'''
 |-