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

!Time  

!Narration  

| In this tutorial, we will learn how to:

* Declare an ''' Array''' and assign value to it.

| * Initialize an''' Array''' during declaration.  

| * To find length of an ''' Array''' and its n'th '''element'''.

| * To print an '''Array'''.  

| * '''Ubuntu Linux 12.04''' OS  

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

|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'''.

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

| 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''' .

| 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 &

| 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 the '''slides'''.

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

| Dollar sign opening curly bracket hash '''arrayname''' within square bracket 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.

| 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 the '''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.'''

| Let's first make the file executable by typing '''chmod''' space '''plus x space 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 3rd element of  '''Array Linux''' is ''' Ubuntu'''.

| In this tutorial, we learnt to:   

| * Declare and assign values to an '''Array'''

|* Initialize an '''Array''' during declaration

|* To find length of an '''Array''' and its '''nth''' element and

| * To print whole ''' Array'''.  

| * the total number of elements

|* print all the elements

|* And print the 5th element.

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