How to detect and protect against files that may contain a virus?

Re: Easy PHP Upload

Can you tell me typically, how do web site owners protect themselves from users who may upload a file containing a
virus?

how many viruses do you know for a linux machine? ;)

you can use mime to check a file before saving on the server

I think he means viruses that can be later downloaded by other users.

To do this you need an antivirus in your server, and use shell_exec() to use it.

maybe :)