Ubuntu 14.04 LTS is quite different... The situation with regard to antivirus programs in Linux depends on how you are using the system. If you are an ordinary user who does web surfing, email, video, etc. you do not need an antivirus program to protect your system. There are 50-75, maybe a few more, known Linux/Unix viruses and/or Trojans, and most are targeted at servers and not desktop machines. Also, at any given time few of these threats are actually circulating in the wild. Newly discovered threats which actually go "in-the-wild" are few and far between. When used as a desktop OS, Linux is very safe and very hard to compromise. It can be done, but it is NOT easy. Generally you have to have direct physical access to the machine to hack one -- successful online attacks against these systems are almost unheard of.

Here is a more or less complete list of known Linux/Unix virus/malware infections:

http://en.wikipedia.org/wiki/Linux_malware

The probability of you running into one of these online is not zero but it is extremely small.

One situation where a Linux user would want to run an AV program (other than if they are running a server) would be if they are sharing a lot of files with Windows users. You can have Windows viruses and malware on a Linux system and it will sit there and do nothing, unless you are running a Windows virtual machine inside Linux and open an infected file inside of it, in which case your VM would become infected. Otherwise no Windows malware can execute on your system. This does not however prevent you from passing it on to someone else. If you share a lot files with Win users, running ClamAV with the Freshclam update service would be advisable. Even though the other users are responsible for their own security, you might stop a number of infections by intercepting a Windows virus or Trojan on a Linux system, before it can be passed on to unsuspecting users elsewhere. ClamAV is not the only Linux AV tool, but it is more or less the gold standard Linux antivirus solution. It runs from the command line unless you also get the ClamTK GUI.

I used to run SNORT which is a very good intrusion detection and defense program, and although it intercepted a number of what appeared to be attempted port scans and malformed TCP/ICMP queries, I found no evidence of anything in the logs which would have actually gotten through the way my system was configured.

DR

Thanks D_runner, I am very new at Linux, but think I am going to like it!