Connects to a wifi ssid available from command prompt on Raspberry pi

connect_to_wifi.sh

#!/bin/bash

# Connects to a wifi ssid available from command prompt on Raspberry pi
# run it with sudo

# you might have to kill wpa_supplicant and dhclient
# sudo killall wpa_supplicant
# sudo killall dhclient

apt -y install wireless-tools wpasupplicant
iw dev wlan0 scan | grep SSID
# another command to get list of available ssid
# iwlist scan | grep -i ssid
SSID="your-sssid"
WPA_CONFIG="./custom_wpa_supplicant.conf"
echo "This script connects to $SSID"
echo "Enter the password for $SSID"
wpa_passphrase $SSID > $WPA_CONFIG
echo "$WPA_CONFIG file generated"
echo "Connecting to $SSID"
#wpa_supplicant -D wext -i wlan0 -c $WPA_CONFIG -B
# some place like stackexchange suggest adding -D wext, but it doesn't work with raspberry pi.
wpa_supplicant -i wlan0 -c $WPA_CONFIG -B &
echo "Obtaining IP address using DHCP"
sleep 10
dhclient wlan0 &