Functions and it significance in Linux scrpiting

Functions:

why functions:

• Don't repeat the same lines of code again and again can be achieved.
• Reduce of script length.
• Maintenance of scripts in case of issue is easy with scripts. Because of single entry maintenance in entire script.

Thumb rules in the Function:

• Must be defined before call.
• Function syntax basically consists of two parts: 

                         1. defining function.

                         2. calling function.      

                                                                            

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#Syntax for 1.defining function:

#Method-1

function function_name ( ) {

                      #code

}

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#Method-2

function_name ( ) {

            #code

}

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#2.calling function.  To call or execute the function which already defined,just mention #function_name  in the line of the script.

real time example:1

#!/bin/bash1

function hello(  ) {

echo "HELLO!!!"

}

hello                 #calling the function

output:

HELLO!!!

Real time example 2: with position parameters

#script     
#/bin/bash
function hello ( ) {
echo "hello $2"
}

hello ram sam zam                 # calling function

output:

hello sam