Linux users, do you ever use any anti-malware programs? - 1

I had some problems with my laptop earlier were harmless; but I realized I'd done some dumb things yesterday. Here's 1 of them:

I was helping a friend with some files she couldn't open. She said they were created on a Mac and asked if I'd convert them. It didn't make sense to me, but I'm used to doing work for people who don't understand software. The files were on a thumb drive.

Her laptop didn't recognize the drive. I popped it in my laptop, backed up the files, and formatted the drive to FAT. When I looked at them, they were just MS Office files.

Her laptop was slow, so I just fired up Virtualbox with Windows 8. I started opening up.docx/.pptx files. I forgot about updating Windows Defender (I hadn't used Windows in months). I only use it to sync files on my iPhone; and since I can do that with cloud-based apps, I rarely use it.

It's unlikely that this drive contained malware written to infect Linux; but at the same time, I also know that thumb drives are one of the easiest ways to do that.

So to make a long story short, can anyone recommend an Linux app that I can use to scan external drives from unknown sources?

I do a lot of troubleshooting for my friends, so I really should be scanning their drives before I open any files. Also, although my earlier issues weren't serious, I still should run a scan anyway.

Thanks for your help!

Added (1). I'm only interested in suggestions that people have tried. I can just browse the software center for a list.

Any of these->http://www.makeuseof.com/tag/free-linux-antivirus-programs/