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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | GIT | COLOPHON |
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GIT-PATCH-ID(1) Git Manual GIT-PATCH-ID(1)
git-patch-id - Compute unique IDs for patches
git patch-id [--stable | --unstable | --verbatim]
Read patches from standard input and compute the patch IDs.
A "patch ID" is nothing but a sum of SHA-1 of the file diffs
associated with a patch, with line numbers ignored. As such, it’s
"reasonably stable", but at the same time also reasonably unique,
i.e., two patches that have the same "patch ID" are almost
guaranteed to be the same thing.
The main usecase for this command is to look for likely duplicate
commits.
When dealing with git diff-tree --patch output, it takes advantage
of the fact that the patch is prefixed with the object name of the
commit, and outputs two 40-byte hexadecimal strings. The first
string is the patch ID, and the second string is the commit ID.
This can be used to make a mapping from patch ID to commit ID for
a set or range of commits.
--verbatim
Calculate the patch ID of the input as it is given, do not
strip any whitespace. Implies --stable and forbids --unstable.
This is the default if patchid.verbatim is true.
--stable
Use a "stable" sum of hashes as the patch ID. With this
option:
• Reordering file diffs that make up a patch does not affect
the ID. In particular, two patches produced by comparing
the same two trees with two different settings for
-O<orderfile> result in the same patch ID signature,
thereby allowing the computed result to be used as a key
to index some meta-information about the change between
the two trees.
• The result is different from the value produced by Git 1.9
and older or produced when an "unstable" hash (see
--unstable below) is configured - even when used on a diff
output taken without any use of -O<orderfile>, thereby
making existing databases storing such "unstable" or
historical patch IDs unusable.
• All whitespace within the patch is ignored and does not
affect the ID.
This is the default if patchid.stable is set to true.
--unstable
Use an "unstable" hash as the patch ID. With this option, the
result produced is compatible with the patch ID value produced
by Git 1.9 and older and whitespace is ignored. Users with
pre-existing databases storing patch IDs produced by Git 1.9
and older (who do not deal with reordered patches) may want to
use this option.
This is the default.
git-cherry(1) shows what commits from a branch have patch ID
equivalent commits in some upstream branch. But it only tells you
whether such a commit exists or not. What if you wanted to know
the relevant commits in the upstream? We can use this command to
make a mapping between your branch and the upstream branch:
#!/bin/sh
upstream="$1"
branch="$2"
test -z "$branch" && branch=HEAD
limit="$3"
if test -n "$limit"
then
tail_opts="$limit".."$upstream"
else
since=$(git log --format=%aI "$upstream".."$branch" | tail -1)
tail_opts=--since="$since"' '"$upstream"
fi
for_branch=$(mktemp)
for_upstream=$(mktemp)
git rev-list --no-merges "$upstream".."$branch" |
git diff-tree --patch --stdin |
git patch-id --stable | sort >"$for_branch"
git rev-list --no-merges $tail_opts |
git diff-tree --patch --stdin |
git patch-id --stable | sort >"$for_upstream"
join -a1 "$for_branch" "$for_upstream" | cut -d' ' -f2,3
rm "$for_branch"
rm "$for_upstream"
Now the first column shows the commit from your branch and the
second column shows the patch ID equivalent commit, if it exists.
git-cherry(1)
Part of the git(1) suite
This page is part of the git (Git distributed version control
system) project. Information about the project can be found at
⟨http://git-scm.com/⟩. If you have a bug report for this manual
page, see ⟨http://git-scm.com/community⟩. This page was obtained
from the project's upstream Git repository
⟨https://github.com/git/git.git⟩ on 2026-05-24. (At that time,
the date of the most recent commit that was found in the
repository was 2026-05-22.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Git 2.54.0.254.g6a4418 2026-05-22 GIT-PATCH-ID(1)
Pages that refer to this page: git(1), git-cherry(1), git-range-diff(1)
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HTML rendering created 2026-05-24 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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