First download envi 4.3 for linux into my home directory, then:

cd
tar -zxvf envi_linux.x86.tar.gz
sudo mkdir /usr/local/rsi
sudo mv idl_6.3 /usr/local/rsi
sudo mv install /usr/local/rsi
sudo mv license /usr/local/rsi
cd /usr/local/rsi
sudo ./install

In the install process, I choose the first option(rsi manner), and it creates some directory by ln command(my option). After the installation, I can run envi by typing command "envi" in terminal, maybe I should create a icon menu in the gnome desktop.