Sometimes, you need to merge multiples repos, but you don’t want to loose your commit history. In this tutorial, it’s basically repoSource1 + repoSource2 = repoTarget.

 

Steps

1. Create source repoSource1, 2 (optionnal)
2. Check existing history on repoSource1, 2
3. Merge repoSource1, 2, to repoTarget
4. Check history on repoTarget

---

1. Create repos 1, 2 (optionnal)

In GIT command line > create repo : create folder > init git > add commit: create file > add to git > commit.

cd git
mkdir repoSource1
cd repoSource1
git init
copy null > file1.txt
git add *
git commit -m "create file1.txt"

cd git
mkdir repoSource2
cd repoSource2
git init
copy null > file2.txt
git add *
git commit -m "create file2.txt"

---

2. Check histories on existing repos

In GIT command line > repo 1 > git log > repo 2 > git log.

cd git/repoSource1
git log

cd git/repoSource2
git log

---

3. Merge repos 1, 2, to repo 3

In GIT command line > create target repo > add remote repo > merge > repeat…

cd git
mkdir repoTarget
cd repoTarget
git init

git remote add repoSource2 ..\repoSource2
git fetch repoSource2
git merge repoSource2/master --allow-unrelated-histories

git log

git remote add repoSource1 ..\repoSource1
git fetch repoSource1
git merge repoSource1/master --allow-unrelated-histories

git log

---

4. Compare histories between repos

In GIT command line > for each repo: > git log > compare commit hash code and date

cd git\repoTarget
git log

cd ..\repoSource1
git log

cd ..\repoSource2
git log

---

Conclusion

With this method, commit history and order (by date) is preserved.

Source

https://github.com/DamienFremont/blog/tree/master/20170614-git-merge-repositories-without-losing-commit-history

References

Merging Two Git Repositories Into One Repository Without Losing File History

http://stackoverflow.com/questions/26502970/merge-multiple-git-repositories-into-one-keeping-branches-history