The mailbox tradition

git am applies patches in mbox format: the format used by mailing-list-driven projects like the Linux kernel and Git itself. Each mbox entry contains a patch plus its commit metadata (author, subject, body), so applying preserves authorship.

Basic apply

git am 0001-feature.patch
git am out/*.patch
git am --3way out/*.patch       # try three-way merge on conflict
git am --keep-cr                # preserve carriage returns

If applying fails, the operation pauses. You can --abort, --skip, or resolve and --continue.

From mail clients

Most mail clients can save messages as mbox. Many maintainers receive patches via mailing list and feed them directly:

cat /var/mail/inbox | git am

Signed-off-by

Convention requires a Signed-off-by trailer for each accepted patch. Add it during apply:

git am --signoff out/*.patch
git config format.signOff true   # always include on format-patch

Direct from URL

curl -sL https://lore.kernel.org/.../t.mbox.gz | gunzip | git am
b4 am https://lore.kernel.org/...    # fancy maintainer tool

b4 is a separate tool that fetches threaded patches and applies in order, recommended for kernel-style workflows.

Reset behavior

If git am hits a conflict, it leaves you mid-apply. Recover:

git am --abort       # restore pre-am state
git am --skip        # skip this patch, move to next
git am --continue    # after editing files

Whitespace handling

git am --whitespace=warn out/*.patch
git am --whitespace=fix out/*.patch
git am --ignore-whitespace out/*.patch

Common mistakes

Applying patches in the wrong order — mbox files are usually pre-numbered (0001-, 0002-); preserve order. Forgetting --3way when the patch was generated against a different base. Mixed line endings: --keep-cr or pre-normalization fixes most cases. Reapplying a patch that was already applied silently no-ops or conflicts.

Related

See "Generating and applying patches" and "Maintaining a patch series with git format-patch".