git-format-patch -3

diff --git a/Documentation/git-patch-id.txt b/Documentation/git-patch-id.txt
index b6fa2a8b399adc80bfa9acbc02c7f5cf5fb88aa6..5389097f73c03347263c3af44497011561c594f2 100644 (file)
--- a/Documentation/git-patch-id.txt
+++ b/Documentation/git-patch-id.txt
@@ -3,7 +3,7 @@ git-patch-id(1)
 
 NAME
 ----
-git-patch-id - Generate a patch ID.
+git-patch-id - Generate a patch ID
 
 SYNOPSIS
 --------
@@ -13,11 +13,17 @@ DESCRIPTION
 -----------
 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, ie two patches that have the same "patch
+the same time also reasonably unique, i.e., two patches that have the same "patch
 ID" are almost guaranteed to be the same thing.
 
 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 string.  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.
+
 OPTIONS
 -------
 <patch>::
@@ -33,5 +39,5 @@ Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
 
 GIT
 ---
-Part of the link:git.html[git] suite
+Part of the gitlink:git[7] suite