linux-kernelorg-stable/scripts/misc-check

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-only

set -e

# Detect files that are tracked but ignored by git.
check_tracked_ignored_files () {
	git -C "${srctree:-.}" ls-files -i -c --exclude-per-directory=.gitignore 2>/dev/null |
		sed 's/$/: warning: ignored by one of the .gitignore files/' >&2
}

check_tracked_ignored_files