aws-cli でやるなら、こんな感じ
update-distribution.sh
# !/bin/bash
DIST_IDS=$(aws cloudfront list-distributions | jq -r '.DistributionList.Items[] | select(.IsIPV6Enabled == false) | .Id')
for DIST_ID in ${DIST_IDS}; do
ETAG=$(aws cloudfront get-distribution --id ${DIST_ID} | jq -r '.ETag')
CONFIG_JSON=$(mktemp)
jq -s '.[0] * .[1]' <(aws cloudfront get-distribution --id "${DIST_ID}" | jq '.Distribution.DistributionConfig') <(echo '{"IsIPV6Enabled": true}') > ${CONFIG_JSON}
aws cloudfront update-distribution --id ${DIST_ID} --distribution-config file://${CONFIG_JSON} --if-match ${ETAG}
rm -f ${CONFIG_JSON}
done