git-submodule: add "sync" command

diff --git a/Documentation/git-diff-tree.txt b/Documentation/git-diff-tree.txt
index 0e45b58d8332cc9f48e0e18165f536adb94a5c6f..5d48664e624f59e0df16121ed67d84939f6d2a31 100644 (file)
--- a/Documentation/git-diff-tree.txt
+++ b/Documentation/git-diff-tree.txt
@@ -49,13 +49,22 @@ include::diff-options.txt[]
 --stdin::
        When '--stdin' is specified, the command does not take
        <tree-ish> arguments from the command line.  Instead, it
-       reads either one <commit> or a pair of <tree-ish>
-       separated with a single space from its standard input.
+       reads lines containing either two <tree>, one <commit>, or a
+       list of <commit> from its standard input.  (Use a single space
+       as separator.)
 +
-When a single commit is given on one line of such input, it compares
-the commit with its parents.  The following flags further affects its
-behavior.  This does not apply to the case where two <tree-ish>
-separated with a single space are given.
+When two trees are given, it compares the first tree with the second.
+When a single commit is given, it compares the commit with its
+parents.  The remaining commits, when given, are used as if they are
+parents of the first commit.
++
+When comparing two trees, the ID of both trees (separated by a space
+and terminated by a newline) is printed before the difference.  When
+comparing commits, the ID of the first (or only) commit, followed by a
+newline, is printed.
++
+The following flags further affects the behavior when comparing
+commits (but not trees).
 
 -m::
        By default, 'git-diff-tree --stdin' does not show
@@ -93,11 +102,11 @@ include::pretty-options.txt[]
        This flag changes the way a merge commit patch is displayed,
        in a similar way to the '-c' option. It implies the '-c'
        and '-p' options and further compresses the patch output
-       by omitting hunks that show differences from only one
-       parent, or show the same change from all but one parent
-       for an Octopus merge.  When this optimization makes all
-       hunks disappear, the commit itself and the commit log
-       message is not shown, just like in any other "empty diff" case.
+       by omitting uninteresting hunks whose the contents in the parents
+       have only two variants and the merge result picks one of them
+       without modification.  When all hunks are uninteresting, the commit
+       itself and the commit log message is not shown, just like in any other
+       "empty diff" case.
 
 --always::
        Show the commit itself and the commit log message even