Setup Wifi of Raspberry Pi via Command Line

# Include or update /etc/network/interfaces (usually those in bold below are to be included or updated in this file

auto wlan0

allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

# Backup Wifi config

sudo cp /etc/wpa_supplicant/wpa_supplicant.conf /etc/wpa_supplicant/wpa_supplicant.conf.orig

# Include in the /etc/wpa_supplicant/wpa_supplicant.conf  

network={
   ssid="YOUR_NETWORK_NAME"
   psk="YOUR_NETWORK_PASSWORD"

}