below). If `--stdin` is also given, input paths are separated
with a NUL character instead of a linefeed character.
+-n, --non-matching::
+ Show given paths which don't match any pattern. This only
+ makes sense when `--verbose` is enabled, otherwise it would
+ not be possible to distinguish between paths which match a
+ pattern and those which don't.
+
+--no-index::
+ Don't look in the index when undertaking the checks. This can
+ be used to debug why a path became tracked by e.g. `git add .`
+ and was not ignored by the rules as expected by the user or when
+ developing patterns including negation to match a path previously
+ added with `git add -f`.
+
OUTPUT
------
<source> <NULL> <linenum> <NULL> <pattern> <NULL> <pathname> <NULL>
+If `-n` or `--non-matching` are specified, non-matching pathnames will
+also be output, in which case all fields in each output record except
+for <pathname> will be empty. This can be useful when running
+non-interactively, so that files can be incrementally streamed to
+STDIN of a long-running check-ignore process, and for each of these
+files, STDOUT will indicate whether that file matched a pattern or
+not. (Without this option, it would be impossible to tell whether the
+absence of output for a given file meant that it didn't match any
+pattern, or that the output hadn't been generated yet.)
+
+Buffering happens as documented under the `GIT_FLUSH` option in
+linkgit:git[1]. The caller is responsible for avoiding deadlocks
+caused by overfilling an input buffer or reading from an empty output
+buffer.
EXIT STATUS
-----------