This is a great thing to have around.
Beware, it will slow your system down a bit if you have lots of files or large files that will be scanned.
Do not use on a development machine where you compile things or it will be very slow to create builds. Your mileage may vary.
Install
1. If you haven’t already downloaded the installer, do as follows:
a) Go to http://www.sophos.com/en-us/products/free-tools.aspx
b) Find Sophos Anti-Virus for Linux Free Edition and click Download. Follow the instructions to download the tarball to a temporary directory, for example /home/myuser/Downloads.
2. Change to the temporary directory and untar the tarball:
tar -xzvf .
If you have a GUI install you can usually Right click and choose Extract Here to avoid having to issue commands in the terminal.
3. Run the install script:
a) You might have to chmod +x the install.sh file before you can run it.
b) Then you can run
sudo ./sophos-av/install.sh
4. The installer guides you through the installation:
■ When prompted for the type of auto-update you want, select Sophos.
■ When prompted for the version you want, select Free.
Sophos Anti-Virus is installed in the directory that you selected.
Uninstall
sudo /opt/sophos-av/uninstall.sh
Official Sopho Antivirus for Linux PDF Manual