Command Line Virus Scanner

Hello, I'm looking for a virus scanner to deploy into a software
development environment. For obvious reasons, it can't be too
intrusive into the OS as this would impact such an environment. For
this reason, I am srongly leaning towards using a command line
scanner and running it overnight by means of a scheduler.

As software developers tend to be a little scornful of Virus-
scanners, I need the product to be fairly automated rather than
relying on a manual process. Is there a way to schedule updates of
signatures and scanning engine from a central resource, perhaps via
ftp or http?

I'm having some trouble finding good reviews of command line
scanners, apart from the usual McAfee and Symantec reports of how
great their own products are. Has anyone got experience of using
such a scanner and any advice they could offer me?

Thanks