To date, Linux has experienced only a small number of viruses.
Some of these viruses exist but aren’t active, and they certainly don’t
propagate like viruses for Windows. As Linux on the desktop reaches critical
mass, there’s a possibility that more viruses will appear, but that may still be
a long ways off. This being the case, you may wonder why Linux has so many
virus scanners.

Linux plays a critical role in server systems and mixed
platform environments. Thus, virus scanners for Linux are essential when
serving e-mail or files to Windows clients. If you can remove the viral threat
before it hits the Windows clients, those clients become safer and less prone
to infection.

One open source virus scanner that deserves mentioning is ClamAV.
You can plug ClamAV directly into e-mail servers, and it will scan for viruses as
the e-mail arrives–before it’s delivered to users’ mailboxes. It also performs
routine scans on files that are served up to Windows clients via Samba sharing.
ClamAV even has plugins for scanning files on the fly as they are accessed via
Samba.

Most Linux distributions ship with ClamAV, so using this
tool is often as simple as installing a pre-packed archive. Another option is
to download it from the ClamAV Web site,
which provides additional links to ClamAV scanners built for Windows and Mac OS
X.

ClamAV works as a client/server system, but you can use it
as a stand-alone scanner as well. To initiate the simplest invocation of
ClamAV, run the following command:

$ clamscan -r -l scan.log /home/user

This will tell ClamAV to perform a recursive scan on the
/home/user directory for any viruses, and it will save the scan results in the
file scan.log. If you’re a Linux administrator, be sure to include ClamAV in
your security arsenal.

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