gitignore_check.sh

#!/usr/bin/env sh

set -uo pipefail
shopt -s globstar

echo -e ".gitignore validation..."

# Get a list of files that exist in the repo but are ignored.

# The --verbose flag also includes files un-ignored via ! prefixes.
# We filter those out with a somewhat awkward `awk` directive.
	# (Explanation: Split each line by : delimiters,
	# see if the actual gitignore line shown in the third field starts with !,
	# if it doesn't, print it.)

# ignorecase for the sake of Windows users.

output=$(git -c core.ignorecase=true check-ignore --verbose --no-index **/* | \
    awk -F ':' '{ if ($3 !~ /^!/) print $0 }')

# Then we take this result and return success if it's empty.
if [ -z "$output" ]; then
    exit 0
else
	# And print the result if it isn't.
    echo "$output"
    exit 1
fi