[PATCH] Document --stdin, -m, -s, and -v flags to git-diff-tree

This updates the usage message string and Documentation/core-git.txt
to describe the new flags added to the git-diff-tree command.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/core-git.txt

@@ -352,7 +352,7 @@ special all-zero sha1.
 
 ################################################################
 git-diff-tree
-	git-diff-tree [-p] [-r] [-z] <tree-ish> <tree-ish> [<pattern>]*
+	git-diff-tree [-p] [-r] [-z] [--stdin] [-m] [-s] [-v] <tree-ish> <tree-ish> [<pattern>]*
 
 Compares the content and mode of the blobs found via two tree objects.
 
@@ -378,6 +378,34 @@ Note that git-diff-tree can use the tree encapsulated in a commit object.
 -z
 	\0 line termination on output
 
+--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.
+
+        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 behaviour.  This does not
+        apply to the case where two <tree-ish> separated with a
+        single space are given.
+
+-m
+	By default, "git-diff-tree --stdin" does not show
+	differences for merge commits.  With this flag, it shows
+	differences to that commit from all of its parents.
+
+-s
+	By default, "git-diff-tree --stdin" shows differences,
+	either in machine-readable form (without -p) or in patch
+	form (with -p).  This output can be supressed.  It is
+	only useful with -v flag.
+
+-v
+	This flag causes "git-diff-tree --stdin" to also show
+	the commit message before the differences.
+
+
 Limiting Output
 
 If you're only interested in differences in a subset of files, for

diff-tree.c

@@ -363,7 +363,8 @@ static int diff_tree_stdin(char *line)
 	return -1;
 }
 
-static char *diff_tree_usage = "diff-tree [-p] [-r] [-z] <tree sha1> <tree sha1>";
+static char *diff_tree_usage =
+"diff-tree [-p] [-r] [-z] [--stdin] [-m] [-s] [-v] <tree sha1> <tree sha1>";
 
 int main(int argc, char **argv)
 {