extip is a braindead simple command line IP fetcher that I wrote to be used in my tmux status bar, because I didn’t want to curl my remote IP every n seconds. It's designed to run as a daemon in the background listening to reachability changes and then updating the remote IP via icanhazip.com. The daemon also provides a simple Mach message interface that the client uses to get the IP, which is then printed to stdout. Dead simple, I’m telling you.

The tool knows exactly three arguments (which are all mutually exclusive):

• --ip (default if nothing is specified) prints the external IP to stdout
• --start starts the extip server (this is done implicitly when you run --ip and there is no running server found)
• --stop stops the extip server

This is what I have in my tmux config to display external, internal and VPN IP:

set -g status-left "#[fg=green]#h @ #[fg=cyan]#(extip | awk '{print "ip " $1}') #[fg=yellow]#(ifconfig en0 | grep 'inet ' | awk '{print "en0 " $2}') #[fg=red]#(ifconfig tun0 | grep 'inet ' | awk '{print "vpn " $2}'"