sudo nano /etc/wpa_supplicant/wpa_supplicant.conf code example

Example 1: raspberry pi wpa_supplicant

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=US

network={
     ssid="Your network name/SSID"
     psk="Your WPA/WPA2 security key"
     key_mgmt=WPA-PSK
}

Example 2: raspberry wifi scan

$ sudo iwlist wlan0 scan

Example 3: raspberry pi scan networks

sudo iwlist wlan0 scan