Problem when strip out the hostname part to leave only the domain

[duke-count]

Thanks for this script. I realized that the internal sed command does not work when the host name is made up of more than three levels, for example: mail.external.example.com should return DOMAIN "example.com" but the value is "external.example. com "

# CERTBOT_DOMAIN is a hostname, not a domain (zone)
# We strip out the hostname part to leave only the domain
DOMAIN="$(sed -r 's/^[^.]+.(.*)$/\1/' <<< "${CERTBOT_DOMAIN}")"

[noonespecial2]

echo something.very.long.example.com | sed -r 's/^([^.]+.)+.(com|net|org)$/\1.\2/'
will return
example.com

for me it did the trick as we own few domains outside of .com it was quick to adapt.