Hi all. First post and just started using Linux hence the confusion. Been a long time MS fan but Vista is a step too far and I refuse to use it after trying to get used to it for months.

Basically it seems a lot of the linux community I've found via google seem to be on a really high horse and state its impossible for linux to get a virus so no need for Antivirus software at all if you use Linux - how is this the case though?

From what I see people base this purely on the fact that linux requires you to enter root details to install a virus and if you dont install a package from an unknown source you're fine. Well... I never had a virus in windows XP using the same principal. I never ran a package from an unknown source and only logged in as a basic user unless I needed admin access! So surely I could state the same thing and say Windows cant get a virus either?!

For a "noob" like me coming over to Linux, I dont know what's a good file and a bad file so for all I know I could be trying to install what I think is a legit package yet it is malicious code opening a back door. So this is where my questions begin...

1. Can people piggy back malicious code onto legit files like they can in Windows?
2. The whole argument about having to provide root details wont hold up in this case as I may run it without knowing
3. To stop me making mistakes whilst learning linux, what points can people give me to make sure the files I open are legit.
4. Does AV exist for file scanning in linux or does the signature scan like in Windows not act the same in Linux because of the way files work?

From what I can see there are currently very few viruses for linux because it's not as popular as windows so few have been written - but thats completely different from people on the net claming viruses DONT exist for linux. Surely if linux takes off then more viruses will be made and new users will make mistakes and get infected? If no AV solution exists then Linux wont take off?

Cheers for any info!