To permanently add environment variables to Linux Mint 13:
1. Go to /home/[username] folder. (Click on Menu –> Home Folder)
2. Click on View menu item on the menu bar
3. Click on Show Hidden Files (You’ll see the shortcut key is Ctrl+H)
4. Right-click on .profile file, select “Open as administrator” sub-menu item.
5. add the export command at the very end of the document.
6. To see the effect of changes, you must first logout and then login again.