How to move files from one git repo to another (not a clone), preserving history

Question

Our Git repositories started out as parts of a single monster SVN repository where the individual projects each had their own tree like so:

project1/branches
        /tags
        /trunk
project2/branches
        /tags
        /trunk

Obviously, it was pretty easy to move files from one to another with svn mv. But in Git, each project is in its own repository, and today I was asked to move a subdirectory from project2 to project1. I did something like this:

$ git clone project2 
$ cd project2
$ git filter-branch --subdirectory-filter deeply/buried/java/source/directory/A -- --all
$ git remote rm origin  # so I don't accidentally overwrite the repo ;-)
$ mkdir -p deeply/buried/different/java/source/directory/B
$ for f in *.java; do 
>  git mv $f deeply/buried/different/java/source/directory/B
>  done
$ git commit -m "moved files to new subdirectory"
$ cd ..
$
$ git clone project1
$ cd project1
$ git remote add p2 ../project2
$ git fetch p2
$ git branch p2 remotes/p2/master
$ git merge p2 # --allow-unrelated-histories for git 2.9+
$ git remote rm p2
$ git push

But that seems pretty convoluted. Is there a better way to do this sort of thing in general? Or have I adopted the right approach?

Note that this involves merging the history into an existing repository, rather than simply creating a new standalone repository from part of another one (as in an earlier question).

Answer 1

If your history is sane, you can take the commits out as patch and apply them in the new repository:

cd repository
git log --pretty=email --patch-with-stat --reverse --full-index --binary -- path/to/file_or_folder > patch
cd ../another_repository
git am --committer-date-is-author-date < ../repository/patch 

Or in one line

git log --pretty=email --patch-with-stat --reverse -- path/to/file_or_folder | (cd /path/to/new_repository && git am --committer-date-is-author-date)

(Taken from Exherbo’s docs)