How to install CLAMAV with update DB script and Scanning on CentOS?

Clam AntiVirus is an open source (GPL) anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail gateways.

It provides a number of utilities including a flexible and scalable multi-threaded daemon, a command line scanner and advanced tool for automatic database updates.

The core of the package is an anti-virus engine available in a form of shared library.

This document will help in installation & configuration of Clamav on Centos.