/etc/network/interfaces

Not much here, just how to use wifi..

When wpa_supplicant is being a b and you just want to connect to wifi..

auto lo
iface lo inet loopback

iface eth inet dhcp

allow-hotplug wlan0
iface wlan0 inet dhcp
   wpa-ssid "SSID"
   wpa-psk"PSKOBVIOUSLY"