See the ping times for all the access points with a single ssid.

ap_tester.sh

#!/bin/sh
SSID=$1
echo Checking access points for ssid $SSID ...
AP_LIST=`sudo iwlist wlan0 scan essid $SSID | grep "Address" | awk '{print $5}'`
echo Found access points:
echo $AP_LIST
for ap in $AP_LIST
do
	echo Connecting to $ap ...
	sudo wpa_cli -i wlan0 bssid 0 $ap
	sudo wpa_cli -i wlan0 reassociate
	sudo wpa_cli -i wlan0 status
	ping -c 10 -s 1024 ic.ac.uk
	echo -n
done
echo done