Difference between revisions of "BASH/C2/Array-Operations-in-BASH/English-timed"

|'''Time'''

|'''Narration'''

| Welcome to the '''spoken tutorial''' on '''Array operations in BASH'''.

| In this tutorial, we will learn how to:Declare an ''' array''' and assign values to it.

| Initialize an''' array''' during declaration.

| To find length of an ''' array''' and its n^th '''element'''.

| To print an '''array'''.

| For relevant tutorials, please visit: spoken hyphen tutorial dot org.

|For this tutorial, I am using:

| '''Ubuntu Linux 12.04''' OS  

| '''GNU Bash''' version '''4.1.10'''

| '''GNU Bash '''version 4 or above is recommended for practice.

|Let us start with the definition of an ''' array''' and its characteristics.

| An '''array''' is a '''variable''' with multiple '''values'''.

| The values can be of same or different types.

| There is no maximum limit for the '''size''' of an '''array'''.

| '''Array''' members need not be consecutive.

| '''Array index''' always starts with '''zero'''.

| We will now see how to declare and assign a '''value''' to an '''array'''.

| The syntax to declare an '''array''' is-  

| '''declare hyphen 'a' arrayname'''

| '''“declare”''' keyword is used to declare an '''array'''.

| It is a built-in '''command''' in '''Bash'''.

| The syntax to assign a value to an '''array '''is-  

| '''Name''' within square brackets '''index''' equals to within single quotes '''value.'''

| Now, let see how to initialize an '''array''' during declaration.

| '''Array''' can be declared and initialized at the same time.

| '''Elements''' Should be separated by a '''space''' .

| Each '''element''' should be within '''parentheses'''.

| The syntax is '''declare hyphen 'a' arrayname equal to within round brackets within single quotes 'element1' , 'element2'''' and '''element3''' .

| Now Type: '''gedit''' '''space array.sh''' space ampersand (&)

| We use the ampersand to free up the '''prompt'''. Press '''Enter'''.

| Type the '''code''' as shown here, in your '''"array.sh"''' file.

| This line declares an '''array''' named '''Linux''' with elements -

'''"Debian", "Redhat", "Ubuntu" and "Fedora"'''.

| Here hyphen '''a''' is a '''flag.'''

| It allows us to read and assign '''values''' to an '''array.'''

| Let us switch back to our '''slides'''.

| The length of an '''array''' can be obtained by this syntax:

| Dollar sign ($) opening curly bracket hash '''arrayname''' within square brackets "At" sign (@) and closing curly bracket.

| The length of the n^th '''element''' can be obtained by this syntax:

| Dollar sign opening curly bracket hash '''arrayname''' within square brackets  'n' and closing curly bracket.

| Here 'n' is the '''element''' number whose length is to be found.

| All the elements of the '''array''' can be printed using this syntax.

| Dollar sign opening curly bracket '''arrayname''' within square brackets 'At' sign (@) and closing curly bracket.

| Now come back to our '''text editor.'''

| This line will display total number of elements in the '''array Linux'''.

| hyphen 'e' enables interpretation of backslash escapes.

| We have included this as we have backslash 'n' at the end of the line.

| The next line displays all the elements of the '''array Linux.'''

| This line displays the 3^rd element of the '''array Linux.'''

| Please note that an '''array''' always starts with '''index''' zero.

| Now, switch to the '''Terminal.'''

| Let's first make the file executable by typing '''chmod''' space '''plus x space array.sh'''. Press '''Enter'''.

| Type: '''dot slash array .sh'''. Press '''Enter.'''

| The '''output''' is displayed.

|The number of elements or the length of the '''array 'Linux' ''' is four.

| The elements of the '''array Linux''' are '''Debian, Redhat, Ubuntu and Fedora.'''

| The third element of  '''array Linux''' is ''' Ubuntu'''.

| And the number of characters in the third element is six, as expected.

| This brings us to the end of this tutorial.

| Let us summarize. Come back to our '''slides'''.

| In this tutorial, we learned to: 

| Declare and assign values to an '''array'''

| Initialize an '''array''' during declaration

| To find length of an '''array''' and its n^th element and

| To print whole '''array'''.

|As an assignment-

| Declare an array '''names''' of length 7 and find:

| the total number of elements

| print all the elements

| and print the 5^th element.

|Watch the video available at the link shown below.

| It summarizes 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.

| The script has been contributed by FOSSEE and spoken-tutorial teams.