Installing CUDA Toolkit 7.5 on Ubuntu 14.04 Linux
The following explains how to install CUDA Toolkit 7.5 on 64-bit Ubuntu 14.04 Linux. I have tested it on a self-assembled desktop with NVIDIA GeForce GTX 550 Ti graphics card. The instruction assumes you have the necessary CUDA compatible hardware support. Depending on your system configuration, your mileage may vary.
Retrieve the CUDA repository package for Ubuntu 14.04 from the CUDA download site and install it in a terminal.
Then you can install the CUDA Toolkit using apt-get.
You should reboot the system afterwards and verify the driver installation with the nvidia-settings utility.
As part of the CUDA environment, you should add the following in the .bashrc file of your home folder.
Now you can copy the SDK samples into your home directory, and build a test sample.
If everything goes well, you should be able to verify your CUDA installation by running the deviceQuery sample.