All the time, I want to know my IP, but find myself Googling “what is my IP” and trying to choose from a bunch of ad-infested sites.
I’ve had ttwagner.com/p0f.php for a while. It shows your IP, hostname (reverse DNS), your browser’s user agent, the headers your browser sent, and, if one was recorded, the most recent OS fingerprint my server saw. (Thanks to p0f.) I should add geolocation data from Maxmind.
But I just whipped up something handy to scripters: ttwagner.com/myip.php. It returns nothing but your IP address, with no formatting. Use it for whatever floats your boat (within reason), but I set it up so I could create a little bash one-liner on my laptop: curl http://ttwagner.com/myip.php && echo "".