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Title of script: More on Arrays in BASH Shell Scripting

Author: Lavitha Pereira

Keywords: video tutorial, Bash shell, Array

Time Narration
00:02 Welcome to the spoken tutorial on More on Arrays in BASH
00:07 In this tutorial, we will learn to
00:10 * Extract an element from an Array
00:13 * Replace an element in an Array
00:16 * Add an element to an Array and
00:19 * Remove an element from an Array
00:22 To follow this tutorial, You should be familiar with the Linux Operating System.
00:28 If not, for relevant tutorials please visit our website which is are shown .
00:34 For this tutorial I am using * Ubuntu Linux 12.04 OS
00:41 and * GNU Bash version 4.1.10
00:45 GNU Bash version 4 or above is recommended for practice .
00:50 Let us see how to “Extract an element from an Array”.
00:55 * The elements in an Array can be extracted from any position.
01:00 * Here, position is the index number.
01:04 * Note that index number always starts from zero
01:09 The syntax is as follows:
01:12 ArrayName within square bracket At sign colon position colon Number of elements to be extracted from the position mentioned.
01:25 Let us understand with the help of an example.
01:29 Open the terminal by pressing Ctrl+Alt and T keys simultaneously on your keyboard.
01:37 Type: gedit space space & (ampersand) sign. Press Enter.
01:47 Now type the code as shown here in your file.
01:54 Let me explain the program.
01:56 This is the Shenbang line
01:59 This declare command declares an array named Linux with elements .
02:06 * Debian,
02:07 * Redhat,
02:08 * Ubuntu and
02:09 * Fedora
02:11 This echo command will print the list of all the elements in the array.
02:16 The next echo command will print the extracted elements.
02:21 The command ${Linux[@]:1:2} will print two elements starting from index one which is Redhat.
02:34 Now switch to the Terminal.
02:36 First let's make the file executable by typing chmod space plus x space .Press Enter.
02:50 Type: dot slash Press Enter.
02:56 We get the output - Original elements in an array Linux: Debian Redhat Ubuntu and Fedora.
03:06 The two elements starting from index one(Redhat): Redhat and Ubuntu
03:12 Let us switch back to the slides
03:15 We will see how to “Replace an element in an Array” .
03:19 An existing element in an Array can be replaced using the following syntax.
03:25 ArrayName within square brackets equals to within single quote, NewWord.
03:34 Here n is the index number or element number.
03:38 Come back to our text editor.
03:41 Linux[2]='Mandriva' .
03:45 This command will replace the third element Ubuntu with Mandriva.
03:51 This echo command will display all elements of array Linux after replacement.

03:58 Come back to our Terminal.
04:01 Let's execute again.
04:04 This displays all elements after replacement : Debian Redhat Mandriva and Fedora .
04:12 Now Switch to the slides.
04:14 We will see how to add an element to an array.
04:18 ArrayName equal to opening round bracket within double quote dollar sign opening curly bracket ArrayName opening square bracket At sign closing square bracket closing curly bracket

space within double quote New_Word_1 space within double quote New_Word_2 and closing round bracket.

04:45 Let us understand this with the help of our example.
04:50 Switch to the code file.
04:52 The highlighted command will append a new element Suse to the array Linux.
04:59 Then we will echo all the elements after appending Suse.
05:05 Switch to the terminal
05:07 Let me clear the prompt.
05:09 We will execute the program again.
05:12 The output is displayed all elements after appending Suse : Debian Redhat Mandriva Fedora and Suse.
05:22 Now, come back to our slides.
05:24 We will see how to remove an element from an array.
05:29 An element can be removed from an array by using the following syntax -
05:35 Unset space ArrayName opening square bracket index number closing square bracket.
05:44 Let us switch to the code file.
05:46 Here we are using the unset command.
05:50 And we will remove the third element Mandriva from the array Linux.
05:56 Then we will echo all the elements again after the removal of Mandriva.
06:02 Now switch to the terminal .
06:04 We will execute the program.
06:07 Here is the list of elements after removing Mandriva
06:12 Debian Redhat Fedora and Suse
06:16 This brings us to the end of this tutorial.
06:19 Come back to our slides.
06:21 Let us summarize.
06:23 In this tutorial, we learned to
06:25 * Extract an element from an Array
06:28 * Replace an element in an Array
06:30 * Add element to an Array and
06:32 * Remove element from an Array
06:36 As an assignment.
06:37 # Declare an array names of length 7 and perform following operations.
06:44 * Extract three elements starting from index two
06:48 * Replace third element with Debian and display
06:55 Append any new name at the end of Array.
06:58 Watch the video available at the link shown below
07:01 It summarizes the Spoken Tutorial project
07:04 If you do not have good bandwidth, you can download and watch it
07:09 The Spoken Tutorial Project Team
07:1 2 Conducts workshops using spoken tutorials
07:15 Gives certificates to those who pass an online test
07:19 For more details, please write to
07:27 Spoken Tutorial Project is a part of the Talk to a Teacher project
07:31 It is supported by the National Mission on Education through ICT, MHRD, Government of India
07:38 More information on this Mission is available at the link shown below.
07:44 The script has been contributed by FOSSEE and spoken-tutorial team.
07:50 This is Ashwini Patil from IIT Bombay signning off.
07:55 Thank you for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14