1. Open your favorite browser, type the following URL, and press Enter:
   https://www.microsoft.com/net/download/linux

2. Select the Install .NET Core SDK 2.x Package button.

3. From the Linux Distribution drop-down list, select Ubuntu 16.04.
   

4. Follow the instructions on the page to install the current SDK or perform the following steps to install.
5. Now open the terminal, type the following command, and press Enter:

      $ curl https://packages.microsoft.com/keys/microsoft.asc | 
      gpg --dearmor > microsoft.gpg

6. If  you have a fresh installation of Ubuntu you might not have curl installed. If not use the following command to install curl:

      $ sudo apt-get install curl 

7. Now, again in the terminal type the following command and press Enter to get the list of files:

      $ sudo mv microsoft.gpg /etc/apt/trusted.gpg.d/microsoft.gpg

8.  Type the following command and press Enter in the terminal:

      $ sudo sh -c 'echo "deb [arch=amd64] 
      https://packages.microsoft.com/repos/
      microsoft-ubuntu-xenial-prod xenial main" > 
      /etc/apt/sources.list.d/dotnetdev.list'

9. Let's update the package list using this command:

      $ sudo apt-get update

10. Finally, let's install the SDK using this command:

      $ sudo apt-get install dotnet-sdk-2.0.2

11. Now we are done with installing the SDK, let's test it using the following command:

      $ dotnet --version 

12. If it's all OK, you should get the following output: