download subdirectory from GitHub

            https://github.com/Username/Repository/tree/master/subdirectory
                                                    |
                                                    v
svn checkout https://github.com/Username/Repository/trunk/subdirectory

References :
Cloning only a subdirectory with git - Stack Overflow

Convert SVN to Git

# apt-get install git-svn




Reference :
Converting a Subversion repository to Git, (7 steps to migrate a complete mirror of svn in git) | JohnAlbin
How to convert from Subversion to Git ➜ Paul Dowman