Have you ever picked up free wifi in a hotel or airport and had the "30 minutes free wifi" and then had the option to pay silly money for an hour? This tip allows you to completely reset that 30 minute grace period, prompted by the following tweet.
The following command will spoof the mac address of your machine, so the captive portal wifi will see your machine as brand new, and reset your free period:
alias freewifi="sudo ifconfig en0 ether `openssl rand -hex 6 | sed 's/\(..\)/\1:/g; s/.$//'`"
This will make a new command called freewifi that changes you MAC address to a random value. Note that to reset your MAC address, you'll either need to reboot, or take a backup of it first (to restore later on):
ifconfig en0 | grep ether
You don't particularly need to understand the details, but if you want to learn, I do cover alias, sudo, piping and sed in my terminal training course.
Enjoy 👍
Credit to Jorge Luis and Web Bos for tweeting this concept into my timeline and further reading here.