diff: document the format of the -O (diff.orderFile) file

diff --git a/Documentation/git-mergetool.txt b/Documentation/git-mergetool.txt
index e846c2ed7f7f862f5324c0e95a2b17dabcaac58d..3622d66488c7de057d32e02cd4cfd21704500822 100644 (file)
--- a/Documentation/git-mergetool.txt
+++ b/Documentation/git-mergetool.txt
@@ -79,6 +79,13 @@ success of the resolution after the custom tool has exited.
        Prompt before each invocation of the merge resolution program
        to give the user a chance to skip the path.
 
+-O<orderfile>::
+       Process files in the order specified in the
+       <orderfile>, which has one shell glob pattern per line.
+       This overrides the `diff.orderFile` configuration variable
+       (see linkgit:git-config[1]).  To cancel `diff.orderFile`,
+       use `-O/dev/null`.
+
 TEMPORARY FILES
 ---------------
 `git mergetool` creates `*.orig` backup files while resolving merges.