How to show Coupon code on checkout page Magento 1.9.x

Many times we need to show coupon code form on checkout page in progress section.This can be achieved by Simple module. first we need to add form on checkout page in following file:

app/design/frontend/{package}/{theme}/template/checkout/onepage/progress.phtml

Above code will Show Coupon form but for Showing success/error message, We need a proper override of couponPostAction action of CartController. We are going to create a small module.

create: app/etc/modules/Pawan_Coupon.xml

app/code/local/Pawan/Coupon/etc/config.xml

app/code/local/Pawan/Coupon/controllers/CartController.php

Final result will be: