-static char *diff_tree_usage =
-"git-diff-tree [-p] [-r] [-z] [--stdin] [-m] [-s] [-v] [--pretty] [-t] [-R] [-B] [-M] [-C] [--find-copies-header] [-O<orderfile>] [-S<string>] [--pickaxe-all] <tree-ish> <tree-ish>";
+static int count_paths(const char **paths)
+{
+ int i = 0;
+ while (*paths++)
+ i++;
+ return i;
+}
+
+static const char diff_tree_usage[] =
+"git-diff-tree [--stdin] [-m] [-s] [-v] [--pretty] [-t] "
+"[<common diff options>] <tree-ish> <tree-ish>"
+COMMON_DIFF_OPTIONS_HELP;