git-patch-id - Compute unique ID for a patch
git patch-id < <patch>
A "patch ID" is nothing but a SHA1 of the diff associated with a patch,
with whitespace and 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
IOW, you can use this thing to look for likely duplicate commits.
When dealing with git diff-tree 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.
The diff to create the ID of.
Written by Linus Torvalds <firstname.lastname@example.org>
Documentation by Junio C Hamano and the git-list
Part of the git(1) suite