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.
/etc/wpa_supplicant/wpa_supplicant.conf
At the bottom of that file you will add the following configuration settings, of course changing out the values to match your networking settings.
network={ ssid="Network Name" psk="Wifi Password" }
Once you have added this simply issue and ifdown and ifup command to wlan0 and you should be connected to your network via Wifi.