Before you install the program you also need to install xterm, if this is not already installed, as this program is sometimes used by the client to view the license. To do this open a Terminal and run the following command:
sudo apt-get install xterm
for Ubuntu:
sudo apt-get install libgtk2.0-0
for Fedora:
sudo yum install xterm glibc.i686 libgcc.i686 libstdc++.i686 glibc-devel.i686 gtk2.i686 libSM.i686
Then you will need to download the "Fortinet VPN client for Linux" software, and extract the content of the archive.
wget http://www.niser.ac.in/docs/forticlientsslvpn_linux_4.4.2332.tar.gz && tar -xzf forticlientsslvpn_linux_4.4.2332.tar.gz
Inside 32bit or 64bit execute the forticlientsslvpn_cli command:
sudo ./forticlientsslvpn_cli --server [server] --vpnuser [user]