Run this as root to configure WiFi for Hypriot https://blog.hypriot.com/

hypriot-wifi.sh

#!/bin/bash

[ ${2} ] || ( echo "usage ${0} <SSID> <PSK>" && exit 1 )

echo -n "Writing /etc/wpa_supplicant/wpa_supplicant.conf... "
echo "network={
  ssid=\"${1}\"
  psk=\"${2}\"
}" > /etc/wpa_supplicant/wpa_supplicant.conf
echo "done"

echo -n "Writing /etc/network/interfaces.d/wlan0... "
echo "iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp" > /etc/network/interfaces.d/wlan0
echo "done"

echo -n "Writing /etc/rc.local... "
echo "#!/bin/sh -e
# rc.local
ifup wlan0
exit 0" > /etc/rc.local
echo "done"

echo "Time to reboot"