AVG Free for Linux: AVG Free offers basic antivirus protection for Linux. It contains limited features, no support, and is only free for private and non-commercial use, but does an adequate job of protecting your system. AVG Free can be run completely from the command line if you choose but does come with a very nice GUI. During my test run of AVG Free, the features I was most impressed by were its real-time protection of my file system, the ability to quickly and easily apply updates via the GUI, the ability to schedule updates, and its ability to scan a great number of files relatively fast.
F-Prot for Linux: F-Prot is free for home users and 100% CLI-based (Command Line Interface), so you execute it with a variety of command switches. The use of a CLI makes f-prot fast and efficient, but tends to pose problems for new Linux users who aren't comfortable operating from the command line. One thing to note is that for experienced Linux users it is fairly easy to setup cron jobs to both update F-Prot and run regular scans of your system.
As with most articles, I am unable to discuss all the available options for Antivirus software for Linux so I end up concentrating on a couple of what I feel are the best options. This invariably leads to many other options being left out. This is not to say Antivirus programs such as Avast! and ClamAV are not viable options. During my research for this article I actually enjoyed the use of Avast! for Linux and would highly recommend it. I did, however, want to mention a 100% CLI-based Antivirus solution in F-Prot (3rd party GUIs are available) and decided to highlight AVG Free for Linux over Avast! for Linux due to the popularity of AVG Free on Windows. New Linux users making the switch from Windows to Linux may recognize the name and feel more comfortable running a piece of software they ran previously on their Windows machines.