Raspberry Pi running Kali Linux, how to setup wifi (Edimax- Realtek RTL8188CUS)

1) Turn on raspberry pi
2) Insert edimax card
In the terminal type command
$lsusb
it will display usb devices connected
Edimx Technology ... EW-7811Un 802.11n [Realtek RTL8188CUS]

3)Enable wlan0 network interface
$sudo nano /etc/network/interfaces

Should be like this:
auto lo

iface lo inet loopback
iface ethc0 inet dhcp

Add the following to interfaces.
auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-ssid "YourNetworkName"
wpa-psk "YourPassword"

4) Disconnect network.
5) Turn Raspberry Pi off  and on. (unplug and plug power cable)

Done!

when device reboots. 
login$ root 
password$ toor

Type
$ifconfig
And it will show that you are connected to wifi :)


Reference:
http://pen-testing-lab.blogspot.com/2013/09/raspberry-pi-and-nano-usb-wifi-ew.html
http://www.suntimebox.com/raspberry-pi-tutorial-course/week-3/day2-1-wireless-network-setup/
http://www.maketecheasier.com/setup-wifi-on-raspberry-pi/
https://www.youtube.com/watch?v=oGbDawnqbP4