nvcc --version command says nvcc is not installed

The problem is [ based on the link you provided] you haven't added it the .bashrc. file so it can be seen:

1. From the terminal:

    nano /home/username/.bashrc
   
    # or
   
    nano /home/$USER/.bashrc
   

2. Inside there add the following:

    export PATH="/usr/local/cuda-8.0/bin:$PATH"
    export LD_LIBRARY_PATH="/usr/local/cuda-8.0/lib64:$LD_LIBRARY_PATH"
   

3. Then do the following to save and close the editor:

    On you keyboard press the following: 
   
    ctrl + o             --> save 
    enter or return key  --> accept changes
    ctrl + x             --> close editor
   

4. Now either do source .bashrc or close and open another terminal

5. Now run nvcc --version

Information:

• .bashrc: is the file read by the terminal before opening and its found in the /home/$USER diretory of the user in question.
• the . before the file means its hidden from view unless you instruct you file manager to show hidden files

The above solution by @George Udosen is fine. If you want to save the manual procedure, you can automize it by the following:

1.create a file "add_to_bashrc"

export CUDA_HOME=/usr/local/cuda
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda/lib64:/usr/local/cuda/extras/CUPTI/lib64
export PATH=$PATH:$CUDA_HOME/bin

2.create a shell script "automate.sh":

(... some installation procedure ...)

cat add_to_bashrc >> ~/.bashrc
. ~/.bashrc

Then you just need to run your shell script

sh automate.sh

Don't forget to check if the CUDA's shortcut (symLink) works correctly. Simply execute:

ls /usr/local/cuda

The answer from @George Udosen is perfect.

Just for increment it, you can also export to /usr/local/cuda which is a symbolic link to /usr/local/cuda-10.1, based on this answer. So, you can also write:

export PATH=/usr/local/cuda/bin${PATH:+:${PATH}}$ 
export LD_LIBRARY_PATH=/usr/local/cuda/lib64${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}