WHMSonic can be installed by root user under the root SSH with the following single command. After you run the following command as a root user, your software will be automatically installed and you can access to WHMSonic at your WHM Root under the plugins menu.
Login to your server root SSH and copy/paste the following command fully and run it.
cd /root/; rm -f installr.sh; wget http://www.whmsonic.com/setupr/installr.sh; chmod +x installr.sh; ./installr.sh
You will receive a final notification after the installation.