set -euo pipefail
export LC_ALL=C
grep_work=$(mktemp -d "${TMPDIR:-/tmp}/grep-example.XXXXXX")
trap 'rm -rf -- "$grep_work"' EXIT
cd "$grep_work"
mkdir -p data
cat > data/allow.txt <<'GRP_INPUT_1'
AB-123
CD-007
GRP_INPUT_1
cat > data/ids.txt <<'GRP_INPUT_2'
AB-7
AB-42
AB-123
CD-007
xAB-123
GRP_INPUT_2

grep -Fx -f data/allow.txt data/ids.txt