Linux operating systems are only used on a very small fraction of desktop/laptop computers – under 2% in April 2015, according to Net Market share – but Linux systems can be bought off the shelf from Dell, and are popular with enthusiasts. Linux is also widely used as a server OS. Although it is considered a more secure platform than Windows, malware for Linux does exist, and is aimed particularly at servers. Additionally, there is the risk of Windows malware passing through Linux systems undetected. For these reasons, we have reviewed the available Linux antivirus products, a number of which are free.