How can I release and renew my DHCP lease from Terminal?
This can also be achieved with the following two commands :

sudo ipconfig set en0 BOOTP
sudo ipconfig set en0 DHCP


You can alias the two together in your bash profile:

alias renew="sudo ipconfig set en0 BOOTP &amp;&amp; sudo ipconfig set en0 DHCP"


So then you just have one command called renew that will release and renew your DHCP.