Create patch or diff file from git repository and apply it to another different git repository

Solution 1:

You can just use git diff to produce a unified diff suitable for git apply:

git diff tag1..tag2 > mypatch.patch

You can then apply the resulting patch with:

git apply mypatch.patch

To produce patch for several commits, you should use format-patch git command, e.g.

git format-patch -k --stdout R1..R2

This will export your commits into patch file in mailbox format.

To generate patch for the last commit, run:

git format-patch -k --stdout HEAD~1

Then in another repository apply the patch by am git command, e.g.

git am -3 -k file.patch

See: man git-format-patch and git-am.