with bash, for the simplest case, if you know what you want to get is a date stamp, you can just use shell expansion

#!/bin/bash

for file in 20[0-9][0-9].[01][0-9].[0-9][0-9]*tgz
do
 echo $file
done


else, if its anything before the first alphabet, 

for file in *tgz
do
 echo ${file%%[a-zA-Z]*}
done


otherwise, you should spell out your criteria for the search.

how can i use regex to get a certain string of a file
Is it possible for a cell phone to communicate with an RFID chip?

I'm looking for a low-powered solution to turn a device on/off wirelessly, using a cell phone.

Example: phone sends signal to RFID chip, circuit board switches on. 

It really looks like Bluetooth will take too much battery, as this will be a portable device.

Any suggestions ? 
