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.

Here is a list of the main features:

* command-line scanner

* fast, multi-threaded daemon with support for on-access scanning

* milter interface for sendmail

* advanced database updater with support for scripted updates and
digital signatures

* virus scanner C library

* on-access scanning (Linux® and FreeBSD®)

* virus database updated multiple times per day (see home page for
total number of signatures)

* built-in support for various archive formats, including Zip, RAR,
Tar, Gzip, Bzip2, OLE2, Cabinet, CHM, BinHex, SIS and others

* built-in support for almost all mail file formats

* built-in support for ELF executables and Portable Executable files
compressed with UPX, FSG, Petite, NsPack, wwpack32, MEW, Upack
and obfuscated with SUE, Y0da Cryptor and others

* built-in support for popular document formats including MS Office and
MacOffice files, HTML, RTF and PDF