No wifi in Raspberry Pi 2 Model B

Scan wifi to check if your Raspberry detects available wifi

iwlist scan | grep <SSID>

If you see your wifi SSID in the out of the command above. Your wifi dongle is fine, and RPi is seeing your wifi.

Open raspi-config

sudo raspi-config

• Select System Options/Wireless LAN
• Select country
• Input SSID and password
• Select OK and Finish
• If RPi asks you to reboot, DON’T.

There is case which raspi-config tell you that it

Could not communicate with wpa_supplicant

This happens quite often with RPi 2b (my model). One workaround is run:

sudo wpa_supplicant -iwlan0 -D wext -c/etc/wpa_supplicant/wpa_supplicant.conf -B
dhclient wlan0

and then repeat the raspi-config procedure above.

Auto connect to wifi after rebooting

To automatically connect to your AP after restart edit the wlan0 interface on your /etc/network/interfaces as follow:

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

sudo reboot

ref: https://unix.stackexchange.com/a/400113

May wifi be with you!