howto use curl to get Internet IP

[Jim]

I want to use  curl to get my Internet IP address, and getting it to 
ddclirent.
Using  getip.com and dyndns.org to get my IP for ddclient, isn't working 
out, they shutout  ddclient  after  awhile from getting my Internet IP  
to send to dyndns.org .
I understand curl can get the Internet IP for ddclient, does anyone know 
of a  HowTo to show me how to do this ?