Look up the IP of your outgoing connections:

_$: curl ifconfig.me
_$: curl getip.com
_$: curl icanhazip.com

Or you can use dig:

_$: dig @resolver1.opendns.com myip.opendns.com +short

Any of these one-liners can be saved as a program in /usr/local/sbin. For example, the last one:

/usr/local/sbin/myip:
---------------------
#/bin/bash -
dig @resolver1.opendns.com myip.opendns.com +short