Difference between revisions of "BASH/C2/Case-statement/English-timed"

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| 00:01
 
| 00:01
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| Dear friends, Welcome to the spoken tutorial on '''Case statement in Bash.'''
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| Dear friends, welcome to the '''spoken tutorial''' on '''Case statement''' in '''Bash.'''
  
 
|-
 
|-
 
| 00:07
 
| 00:07
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| In this tutorial, we will learn Importance of '''case statement''' Syntax of '''case statement''' with an Example
+
| In this tutorial, we will learn:
 +
* Importance of '''case statement'''
 +
* Syntax of '''case statement''' with an example.
  
 
|-
 
|-
 
| 00:17
 
| 00:17
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| To follow this tutorial, you should have knowledge on Basics of '''Shell Scripting'''.
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| To follow this tutorial, you should have knowledge on basics of '''Shell Scripting'''.
  
 
|-
 
|-
 
|00:23
 
|00:23
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|If not, for relevant tutorials please visit our website which is as shown.
+
|If not, for relevant tutorials, please visit our website which is as shown.
  
 
|-
 
|-
 
| 00:29
 
| 00:29
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| For this tutorial I am using ''' Ubuntu Linux''' 12.04''' Operating System''' and '''GNU BASH''' version 4.1.10
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| For this tutorial, I am using:
 +
* ''' Ubuntu Linux''' 12.04''' Operating System''' and  
 +
* '''GNU BASH''' version 4.1.10
  
 
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|-
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| 00:47
 
| 00:47
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|  The '''Bash '''shell has two forms of conditional statements. '''if statement''' and  '''case statement. '''
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|  The '''Bash''' '''shell''' has two forms of '''conditional statements'''. '''if statement''' and  '''case statement.'''
  
 
|-
 
|-
 
| 00:56
 
| 00:56
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|'''Case statement '''can be alternately used in place of '''if-else statement'''
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|'''Case statement '''can be alternately used in place of '''if-else statement'''.
  
 
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|01:15
 
|01:15
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|'''case space $(dollar)VARIABLE space in''' '''match_1''' close round brackets space '''commands''' and semicolon twice
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|'''case''' space '''$(dollar) VARIABLE''' space '''in''' '''match_1''' close round brackets space '''commands''' and semicolon twice
  
 
|-
 
|-
 
|01:27
 
|01:27
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|'''match_n''' close round bracket space '''commands''' and semicolon twice '''asterisk''' close round bracket space '''command_to_execute_by_default''' and semicolon twice '''esac'''
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|'''match_n''' close round bracket space '''commands''' and semicolon twice '''asterisk''' close round bracket space '''command_to_execute_by_default''' and semicolon twice '''esac'''.
  
 
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|01:54
 
|01:54
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|It will check if any one of these strings matches '''VARIABLE. '''
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|It will check if any one of these '''strings''' matches '''VARIABLE. '''
  
 
|-
 
|-
 
|02:01
 
|02:01
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|If yes, then all the commands until the double''' semicolon (;;) '''are executed.
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|If yes, then all the '''commands''' until the double''' semicolon (;;) '''are executed.
  
 
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| 02:32
 
| 02:32
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| I have already typed the program.So, I will open the file '''case.sh'''  
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| I have already typed the program. So, I will open the file '''case.sh'''.
  
 
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|-
 
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|02:47
 
|02:47
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|The location of '''bash '''is different in other '''Linux''' flavours like '''CentOS, RedHat etc.'''
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|The location of '''bash '''is different in other '''Linux''' flavors like '''CentOS, RedHat etc.'''
  
 
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|03:22
 
|03:22
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|The output is piped to '''sort -rk5''', which sorts the fifth column in reverse order.
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|The '''output''' is piped to '''sort -rk5''' which sorts the fifth column in reverse order.
  
 
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| 04:48
 
| 04:48
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| Now go to the''' terminal,''' to make the file executable.
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| Now go to the''' terminal''' to make the file executable.
  
 
|-
 
|-
 
|04:52
 
|04:52
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|Type''' chmod space plus x space case dot sh '''
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|Type: ''' chmod plus x case dot sh '''
  
 
|-
 
|-
 
|04:57
 
|04:57
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|Type '''dot slash case dot sh'''
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|Type: '''dot slash case dot sh'''
  
 
|-
 
|-
 
| 05:02
 
| 05:02
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| '''Everything is OK.'''Note that the output will vary depending on your system diskspace.
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| '''Everything is OK.''' Note that the output will vary depending on your system disk space.
  
 
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|05:31
 
|05:31
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|In this tutorial we learnt, Importance of''' case statement''', Syntax of '''case statement''',  With the disc space example
+
|In this tutorial, we learnt:
 +
* Importance of''' case statement'''  
 +
* Syntax of '''case statement''' with the disc-space example.
  
 
|-
 
|-
 
| 05:41
 
| 05:41
−
| As an assignment.
+
| As an assignment:
  
 
|-
 
|-
 
|05:42
 
|05:42
−
|Write a menu driven program for mathematical calculation
+
|Write a menu driven program for mathematical calculation;
  
 
|-
 
|-
 
|05:47
 
|05:47
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| It should take user inputs '''a '''and '''b'''
+
| It should take user inputs '''a '''and '''b''';
  
 
|-
 
|-
 
|05:51
 
|05:51
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| It should ask for mathematical opertator (plus +, minus -, division / and multiplication *). Do the calculation,  Print the output
+
| It should ask for mathematical operator (plus +, minus -, division / and multiplication *). Do the calculation,  print the output.
  
 
|-
 
|-
 
| 06:02
 
| 06:02
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| Watch the video available at the link shown below
+
| Watch the video available at the link shown below.
  
 
|-
 
|-
 
|06:06
 
|06:06
−
|It summarises the Spoken Tutorial project
+
|It summarizes the Spoken-Tutorial project.
  
 
|-
 
|-
 
|06:08
 
|06:08
−
|If you do not have good bandwidth, you can download and watch it
+
|If you do not have good bandwidth, you can download and watch it.
  
 
|-
 
|-
 
| 06:14
 
| 06:14
−
| The Spoken Tutorial Project Team
+
| The Spoken Tutorial Project team:
  
 
|-
 
|-
 
| 06:16
 
| 06:16
−
|Conducts workshops using spoken tutorials .Gives certificates to those who pass an online test
+
|Conducts workshops using spoken tutorials ;
 +
Gives certificates to those who pass an online test.
  
 
|-
 
|-
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|06:31
 
|06:31
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| Spoken Tutorial Project is a part of the Talk to a Teacher project
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| '''Spoken Tutorial''' project is a part of the '''Talk to a Teacher''' project.
  
 
|-
 
|-
 
| 06:35
 
| 06:35
−
|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
+
|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
  
 
|-
 
|-
 
| 06:48
 
| 06:48
−
| The script has been contributed by FOSSEE and spoken-tutorial team
+
| The script has been contributed by FOSSEE and spoken-tutorial team.
  
 
|-
 
|-
 
| 06:53
 
| 06:53
−
|This is Ashwini from IIT Bombay.Thank you for joining.
+
|This is Ashwini from IIT Bombay. Thank you for joining.
  
 
|}
 
|}

Revision as of 23:49, 5 July 2015

Time Narration
00:01 Dear friends, welcome to the spoken tutorial on Case statement in Bash.
00:07 In this tutorial, we will learn:
  • Importance of case statement
  • Syntax of case statement with an example.
00:17 To follow this tutorial, you should have knowledge on basics of Shell Scripting.
00:23 If not, for relevant tutorials, please visit our website which is as shown.
00:29 For this tutorial, I am using:
  • Ubuntu Linux 12.04 Operating System and
  • GNU BASH version 4.1.10
00:39 Please note, GNU Bash version 4 or above is recommended to practice this tutorial.
00:47 The Bash shell has two forms of conditional statements. if statement and case statement.
00:56 Case statement can be alternately used in place of if-else statement.
01:03 The case statement is preferred when there are many items to select from.
01:09 It is usually used to implement menus in a script.
01:14 Let us see the syntax.
01:15 case space $(dollar) VARIABLE space in match_1 close round brackets space commands and semicolon twice
01:27 match_n close round bracket space commands and semicolon twice asterisk close round bracket space command_to_execute_by_default and semicolon twice esac.
01:45 The VARIABLE is compared to match_1.
01:48 If it does not match, it moves on to the next case which is match_n.
01:54 It will check if any one of these strings matches VARIABLE.
02:01 If yes, then all the commands until the double semicolon (;;) are executed.
02:07 If neither match VARIABLE, the commands associated with the asterisk are executed.
02:14 It is the default case condition because the asterisk will match all strings.
02:21 esac marks the end of case block.
02:26 Let us understand case statement with an example.
02:32 I have already typed the program. So, I will open the file case.sh.
02:38 The program prints a warning message when the disk space reaches a certain limit.
02:45 This is the shebang line.
02:47 The location of bash is different in other Linux flavors like CentOS, RedHat etc.
02:55 Previously used /bin/bash points directly to the binary file.
03:01 env used here, abstracts the true location where bash is located.
03:07 This shebang line improves the portability of the script on any GNU/Linux system.
03:16 df -(hyphen)h displays disk space usage in human readable form.
03:22 The output is piped to sort -rk5 which sorts the fifth column in reverse order.
03:31 The output is then passed to awk 'FNR == 2 {print $5}'
03:38 which extracts the fifth field of the second line.
03:43 Eventually, the output is passed to cut -(hyphen)d “% -(hyphen)f1” to strip out % sign.
03:55 This is the first line of case statement.
03:59 Here, we compare the space between 0 and 69.
04:04 If match is found, it prints "Everything is OK”
04:08 Next, it compares the space between 70 and 89 or from 91 to 98;
04:17 If match is found, it prints “Clean out. There's a partition that is $(dollar)space % full.”
04:27 Here, it compares the space with 99.
04:30 If match is found, it prints “Hurry. There's a partition at $(Dollar) space %!”
04:39 This is the default case condition because the asterisk will match all strings.
04:45 And this is the end of case statement.
04:48 Now go to the terminal to make the file executable.
04:52 Type: chmod plus x case dot sh
04:57 Type: dot slash case dot sh
05:02 Everything is OK. Note that the output will vary depending on your system disk space.
05:10 In my machine, as match is found between 0 and 69, it prints Everything is OK.
05:18 Check the message printed on your machine.
05:20 You will be able to understand which case statement was executed.
05:27 This brings us to the end of this tutorial. Let us summarize.
05:31 In this tutorial, we learnt:
  • Importance of case statement
  • Syntax of case statement with the disc-space example.
05:41 As an assignment:
05:42 Write a menu driven program for mathematical calculation;
05:47 It should take user inputs a and b;
05:51 It should ask for mathematical operator (plus +, minus -, division / and multiplication *). Do the calculation, print the output.
06:02 Watch the video available at the link shown below.
06:06 It summarizes the Spoken-Tutorial project.
06:08 If you do not have good bandwidth, you can download and watch it.
06:14 The Spoken Tutorial Project team:
06:16 Conducts workshops using spoken tutorials ;

Gives certificates to those who pass an online test.

06:23 For more details, please write to contact@spoken-tutorial.org
06:31 Spoken Tutorial project is a part of the Talk to a Teacher project.
06:35 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
06:48 The script has been contributed by FOSSEE and spoken-tutorial team.
06:53 This is Ashwini from IIT Bombay. Thank you for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14

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