コレが全部通る正規表現教えて

regex_question_20130930.sh

REGEX="id=123[^0-9]"

echo "id=123"      | grep $REGEX &>/dev/null && echo PASS
echo "id=123&a=b"  | grep $REGEX &>/dev/null && echo PASS
echo "id=1234&a=b" | grep $REGEX || echo PASS
echo "id=1234"     | grep $REGEX || echo PASS