doc: clarify ignore rules for git ls-files

Explain that `git ls-files --ignored` requires at least one
of the `--exclude*` options to do its job.

Signed-off-by: Andreas Heiduk <asheiduk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt
index 3ac3e3a..f3474b2 100644 (file)
--- a/Documentation/git-ls-files.txt
+++ b/Documentation/git-ls-files.txt
@@ -53,7 +53,8 @@ OPTIONS
        Show only ignored files in the output. When showing files in the
        index, print only those matched by an exclude pattern. When
        showing "other" files, show only those matched by an exclude
-       pattern.
+       pattern. Standard ignore rules are not automatically activated,
+       therefore at least one of the `--exclude*` options is required.
 
 -s::
 --stage::