rpi3_wifi

# scan wifi
sudo iwlist wlan0 scan

# modify file to auto connect to wifi
sudo vim /etc/network/interfaces
# change wlan0 like this
auto lo
iface lo inet loopback

iface eth0 inet manual

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


# and change another file
:tabnew /etc/wpa_supplicant/wpa_supplicant.conf
# add this to bottom of file
network={
    ssid="name"
    psk="password"
    priority=1
    proto=RSN
    key_mgmt=WPA-PSK
    pairwise=CCMP
}

network={
    ssid="name"
    psk="password"
    priority=2
    proto=RSN
    key_mgmt=WPA-PSK
    pairwise=CCMP
}
# close

#check  if config file is valid
sudo ifdown wlan0
sudo ifup wlan0

# check ip
ifconfig wlan0
curl ipinfo.io/ip