Git doesn't support downloading parts of the repository. You have to download all of it. But you should be able to do this with GitHub. In GitHub when you view a file it has a link to the "raw" version of the file. Now all you have to do is copy the URL in your browser. Which can be done in two ways:
$ wget --no-check-certificate --content-disposition https://copied-URL/
$ curl -LJO https://copied-URL/
For more information regarding the git life cycle please go through this link: