Keep ClamAV up to date with its latest virus database update.
It features a command line interface for scanning files, updating the virus definitions, and a daemon for faster scanning needed on high performance systems.
Unlike most antivirus products, ClamAV requires no yearly subscription fee, and is completely free with source code to anyone who wishes to use it. Because ClamAV is released under the GPL v2 license, you must follow all license requirements if you alter the ClamAV source code, or use it in your own projects.