wpa_cli tricks:
# Connect to an open network
add_network # creates a network, say number 1
set_network 1 ssid "MY_SSID"
set_network 1 key_mgmt NONE
select_network 1
# Switch between networks in a wpa_supplicant.conf file
select_network x # x = network to use
# Alternatively, enable the network to keep others online too
enable_network x