Usage example

[szepeviktor]

May I put this into the Wiki?
This script outputs only the SLD part from a list of domain names.
So if you have subdomain.example.co.uk on your list, the output will be example.co.uk.

# Prepare the list for finding second-level domains
Publicsuffix_regexp() {
    local LIST_URL="https://publicsuffix.org/list/public_suffix_list.dat"

    # Download list,
    #   remove empty lines and comments,
    #   escape dots, asterisks and add SLD regexp
    wget -qO- "$LIST_URL" \
        | grep -v "^\s*$\|^\s*//" \
        | sed -e 's/\./\\./g' -e 's/\*/.*/' -e 's/^\(.*\)$/[^.]\\+\\.\1$/'
}

Publicsuffix_regexp | grep -o -f - "$YOUR_DOMAINS"

I use it for registration expiry purposes.

[weppos]

@szepeviktor thanks for your contributions. I'm closing this, as we don't currently add usage examples or libraries to the wiki.

Also double check your code properly reflects the formal algorithm, including the exceptions. Or you may get inaccurate results.