Linux anti-virus programs do not work like Windows ones. In Windows, the AV
works in the background and then scans files as they are downloaded or in
emails. In Linux, files have to be manually scanned which seems like a hassle,
but then again viruses in Linux are rare.

You can get Linux to scan files in the background like Windows, but it is hard
to setup and its usefulness is questionable. It requires a separate module
called dazuko. AVG also makes a Linux anti-virus program, BTW. Clam is the best
Linux antivirus program. If you use KDE, use Klam.

I do not use an anti-virus program, but have in the past. I have even managed to
get dazuko to work once or twice, but it has always seemed like wasted effort.
However, when I have Windows running in VirtualBox, I use one there. I prefer
AVG for Windows use.

I know that as a good netizen, I should use an anti-virus program, but have come
to the cynical conclusion that Windows users get what they deserve. It is a
price that they are willing to pay to use the OS, but that should not dictate my
habits in Linux.