I wanted to move from an bulky svn repository containing several projects to smaller git repositories to allow for easy distribution of the files and tracking of the code. Of course, while doing that, I wanted to keep the file history... I could not use the classic filter-branch as I wanted to extract only a few files withing a directory.
So... First step is to checkgout the svn repository with git :
git svn clone $SVN_REPO_URL cd $SVN_REPO_URL
or, if you have already done it, you can update the repository with
cd $SVN_REPO_URL git svn rebase
then you would extract the history of the desired files into a patch file
git log --pretty=email --patch-with-stat --reverse --full-index --binary path/to/file* > /tmp/patch
This will generate a full patch to the file, from its creation to the last commit. The (old) path in the patch file are relative to the old svn structure. Thus one could change it to reflect the new desired path structure
sed -i -e 's/old\/path\///g' /tmp/patch
for example to remove all the path for the new repository
And after creating a new git repository, and within the repository, you can replay the file creation and modification with
mkdir $GIT_REPO cd $GIT_REPO git init . git am < /tmp/patch
This will recreate the files, with their history, in the newly created git repository.