Functions in Bash

A function which can also be referred to as subroutine or procedure is a block of code used for specific tasks. The function also has a property called re-usability. Bash script also provides functions.

Syntax:

funcationName(){    
  // scope of function
}

functionName  //calling of function

#1. Bash – Create Function Example

Create your first function in shell script showing output “Hello World!”. Create a shell script “script.sh” using following code.

#!/bin/bash

funHello(){
    echo "Hello World!";
}

# Call funHello from anywhere in the script like below

funHello

Le’t execute script

$ ./script.sh

Hello World!

#2. Bash – Function with Argument

The passing argument to functions is similar to pass an argument to command from shell. Functions receives arguments to $1,$2… etc. Create a shell script using following code.

#!/bin/bash

funArguments(){
   echo "First Argument: " $1
   echo "Second Argument: " $2
   echo "Third Argument: " $3
   echo "Fourth Argument: " $4
}

# Call funArguments from anywhere in the script using parameters like below

funArguments 1 Welcome to TecAdmin 

Let’s execute the script with the bash shell.

$ ./script.sh

First Argument : 1
Second Argument : Welcome
Third Argument : to
Fourth Argument : TecAd,om

For more detailed uses of function in bash scripts visit here.