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 3ac3e3a77d171d55a2992b263e03350cf4c08b3d..f3474b2ede0b61d62fef2c52c55d6d64cac170b9 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::