To Install the Avast product on your Debian server You will first need to Add the Avast repository to the system repositories. To do this use the following;
# echo "deb http://deb.avast.com/lin/repo debian release" \ >> /etc/apt/sources.list
Next we will need to download the GPG key from https://files.avast.com/files/resellers/linux/avast.gpg this will allow you to receive the VPS updates. To do this use wget as follows;
Next we will need to update with apt-get update
Once that is completed we are ready to install the avast product.
Apt-get install avast
Once that is complete we will then need to copy the license file to the /etc/avast directory.
cp /path/to/license.avast.lic /etc/avast in my case it is in the /mnt directory. Also you can start the avast services at this time.
NOTE****** Be sure to replace /path/to/license.avastlic with YOUR actual path to the license file on your server.
Also if you like you can install other products such as the avast-fss and the avast-proxy. Here we will install the avast-fss (avast file system security).