You don't get down off an elephant, you get down off a duck!
The same joke applies whenever somebody asks "How do you install anti-virus in Linux?". You don't install anti-virus in Linux, you install anti-virus in Windows.
Lately, when you try to tell people that they don't need to install anti-virus in Linux, they say "People tell me that, but I want it anyway".
So, let me explain why you don't need anti-virus in Linux, and to do this we have to start with an explanation of what a virus is.
A virus is a malicious computer program, written to perform some sort of criminal activity with your computer. This can include deleting your data, but these days viruses are much more subtle. They don't cause mindless destruction. They use your computer to illegally profit their writers. As such, they attempt to evade detection, because as soon as you detect them you would run an anti-virus scan and delete them! They also always set themselves to start up when the computer starts up, which is dependent on them gaining administrator access to your computer.
Once they have administrator access, they can evade detection until you run an anti-virus program that knows about them.
We all know that Windows programs don't run in Linux. A virus is simply a Windows program, so it doesn't run in Linux. This is because Linux programs use a different format to Windows programs - Windows programs use the EXE format, Linux programs use the ELF format. Even if Linux could understand EXE, it would be pointless because the programs would be trying to interact with Windows shared libraries or (in the case of viruses) the Windows internals directly, which of course are not present on Linux.
If you download a Windows trojan and double-click it on a Linux system, you get a "Cannot open file 'boobs.jpg.exe'" message. Linux doesn't understand the EXE executable format, only the ELF executable format. If you install a program like Wine, that can understand the EXE format and also allow the use of Windows shared libraries, you'll still find that viruses won't work. This is because the viruses try to gain access to the running instance of Windows, and of course there isn't one.
Or, if they are programmed more conventionally, they manage to install themselves into a system-wide area in what they think is your Windows installation, but is actually just a Wine installation in your home directory. The result is that the virus might keep running until you quit Wine or until you restart. If you restart and then run a Wine program, the virus still won't be run, because Wine doesn't perform a Windows startup sequence.
Even if a Windows virus was aware of Wine running on Linux, it still could not start itself up when Linux starts up. Linux's startup sequence requires root access, and there has never been any known way of getting a Windows program to give Wine the higher privileges necessary to modify the Linux startup sequence.
This is all fine in theory. I'm a big fan of the documentary series "Medical Mavericks", which documents the lives of medical self-experimenters, so I'll put my own computer on the line.
I started with a brand-new GNU/Linux computer that I used every day from its build-date in January, to early July. A virus scan with ClamAV today yields a clean result. No viruses. Also, Wine is not running at the moment, so no Windows viruses are resident. I also had a Windows computer that my father was using (verified as clean on the build-date of the Linux computer), but I had to stop the test early because it contracted zlob.downloader - a nasty form of Windows virus that actually downloads more viruses.
Both computers were connected via local area network, and only the Windows computer had a personal firewall. The whole LAN has a firewall. Neither computer ran any sort of anti-virus between the start of the test and the end of the test.
But what would happen if I took a Windows virus and actually tried explicitly running it in Wine? I found a virus on a Facebook group, downloaded it, and double-clicked it. Wine started running, and then immediately ended. Neither wine, nor wineserver, nor the virus program itself, was running anymore. I tried running Wine in a terminal, but no error messages were output. The virus started running, and then immediately stopped running. I checked again with ClamAV, and it found the copy of the virus that I was trying to run, but it didn't find any copies in /etc/init.d or anywhere else on my hard disk.
So do you need an anti-virus program in Linux? No, absolutely not! Windows viruses do not run. There are no Linux viruses, partly because there's no place in the system for a Linux virus to hide, and partly because of all the security features in a modern Linux system. There are few Mac viruses, and all of those take advantage of Apple-specific security blunders.
If you still want to install an anti-virus program on your first desktop Linux system, after all I've told you, then I'm concerned that you won't be able to break the Windows habit. But I'm sure that most, if not all of you, now understand more about why anti-virus is useless on Linux, and I warmly wish you good luck with the rest of your Linux adventures.