Clam Antivirus (ClamAV) is probably the most well-known Linux/UNIX antivirus, but has a small draw-back for some: it's a command-line application. ClamTk comes to the rescue: it is a GUI front-end for Clam Antivirus.

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.