Generate a Git patch for a specific commit

Use git format-patch -1 COMMIT to export one ordinary commit as an email-format patch. It includes the change, author information, and commit message. Applying it with git am creates a new commit; it does not guarantee the original commit ID because the parent and committer metadata can differ.

Replace COMMIT below with an actual commit ID or reference.

Export one commit or a series

# One selected commit
git format-patch -1 COMMIT

# The most recent three commits
git format-patch -3

# Commits on feature-x that are not reachable from main
git format-patch main..feature-x

# Write one patch into a directory
git format-patch -1 COMMIT -o patches/

The output usually has a name such as 0001-Fix-login-bug.patch. format-patch exports non-merge commits; do not assume it preserves a merge commit's topology. Review which commits the range selects before sending the files.

Apply an email-format patch

On the target branch, with a clean working tree:

git am 0001-Fix-login-bug.patch

Alternatively, request a three-way fallback when the necessary base objects are available:

git am --3way 0001-Fix-login-bug.patch

These are alternative ways to apply the same patch, not consecutive commands. git am retains the patch's author and message while creating a commit in the target repository.

For file changes without creating a commit:

git apply --check 0001-Fix-login-bug.patch
git apply 0001-Fix-login-bug.patch

Review and stage those changes yourself if you later want to commit them.

Choose email format or a raw diff

For example:

git show --format= --binary COMMIT > fix.patch
git apply --check fix.patch

Plain git show COMMIT normally includes a commit header, so --format= makes the raw-diff intent explicit. For a merge commit, choose the parent or snapshot comparison deliberately rather than relying on its default combined diff.

FAQ

What if git am encounters a conflict?

If a three-way fallback cannot resolve it, edit the conflicted files, stage the result with git add, and run git am --continue. Use git am --abort to return to the pre-application state. Three-way application requires the patch's base blobs to exist locally; it cannot invent missing context.

How are binary changes handled?

format-patch normally includes applicable binary changes unless configured or requested otherwise, such as with --no-binary. For a raw diff, generate it with git diff --binary or git show --binary. Modern git apply accepts binary patches without an extra --binary option; that option is retained for compatibility.

Can I email the patch to a maintainer?

Yes. Email-based review is the purpose of this format, and git send-email supports sending it through a configured mail service. Follow the project's contribution instructions and inspect the patch for unintended content before sending.

See git-format-patch, git-am, git-apply, and git-show.