- Function is a series of instruction/commands. Function performs particular activity in shell i.e. it had specific work to do or simply say task.
- When program gets complex we need to use divide and conquer technique. It means whenever programs gets complicated, we divide it into small chunks/entities which are known as functions.
Syntax:
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function-name ( ) { command1 command2 ..... ... commandN return } |
Where function-name is name of your function, that executes series of commands. A return statement will terminate the function.
Ex1:
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#!/bin/sh SayHello() /* Define your function here */ { echo "Hello Selva, Have a nice day" return } SayHello /* Invoking Function here */ |
Output:
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Hello Selva, Have a nice day. |
Note:
To execute this SayHello() function just type it name as mentioned in above example.
Ex2:
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#!/bin/sh hello() { echo "HELLO Selva GOOD MORNING" return } hai() { echo "HAI Selva" return } hai hello exit hai |
Output:
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HAI Selva HELLO Selva GOOD MORNING |
Note:
In the above example, the function “hai” has been called again after the “exit” statement. So, script did not execute the “hai” again. Whatever the function/commands called after the exit statement will not be executed.