Documentation / git-patch-id.txton commit move show_pack_info() where it belongs (77d3ece)
   1git-patch-id(1)
   2===============
   3
   4NAME
   5----
   6git-patch-id - Compute unique ID for a patch
   7
   8SYNOPSIS
   9--------
  10'git-patch-id' < <patch>
  11
  12DESCRIPTION
  13-----------
  14A "patch ID" is nothing but a SHA1 of the diff associated with a patch, with
  15whitespace and line numbers ignored.  As such, it's "reasonably stable", but at
  16the same time also reasonably unique, i.e., two patches that have the same "patch
  17ID" are almost guaranteed to be the same thing.
  18
  19IOW, you can use this thing to look for likely duplicate commits.
  20
  21When dealing with git-diff-tree output, it takes advantage of
  22the fact that the patch is prefixed with the object name of the
  23commit, and outputs two 40-byte hexadecimal string.  The first
  24string is the patch ID, and the second string is the commit ID.
  25This can be used to make a mapping from patch ID to commit ID.
  26
  27OPTIONS
  28-------
  29<patch>::
  30        The diff to create the ID of.
  31
  32Author
  33------
  34Written by Linus Torvalds <torvalds@osdl.org>
  35
  36Documentation
  37--------------
  38Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
  39
  40GIT
  41---
  42Part of the linkgit:git[1] suite