Add these alias to your shell startup and you can find your public IPv4 or IPv6 without visiting any 3rd party web site from your Linux, macOS or Unix machine:

alias what_is_my_ip='dig +short txt ch whoami.cloudflare @1.0.0.1'
alias what_is_my_ip_v4='what_is_my_ip'
alias what_is_my_ip_v6='dig -6 TXT +short o-o.myaddr.l.google.com @ns1.google.com'

Run it as:

what_is_my_ip
what_is_my_ip_v4
what_is_my_ip_v6