I recently purchased a Raspberry Pi 3 (Not that I needed another one as I already had two previous models laying around doing a whole lot of nothing.) and needed to get it connected to my network.
While I work with linux on a daily basis, it had been a while since I configured a linux device to connect to Wifi (Such as my original Raspberry Pi, and Pi2). Looking into this, it seems like it has gotten a whole lot easier over the years even with out the GUI.
In order to get the Raspberry Pi 3 connected you will just need to edit the following file. I started off with an install of Jessie Lite, and with this install I didn’t even have to go through the hassle of connecting via ethernet first and installing additional drivers which was a huge plus.
At the bottom of that file you will add the following configuration settings, of course changing out the values to match your networking settings.
Once you have added this simply issue and ifdown and ifup command to wlan0 and you should be connected to your network via Wifi.