GTFS mirroring tool. This allows us to keep the GTFS data from Adelaide Metro in a revision control system (so we could look up historical data).
It should be trivial to adapt this to monitor another public transit system.
This is best used in a daily crontab.
You shouldn't need to run this script yourself though, I already provide a repository at https://github.com/gtfsdata/adelaidemetro-gtfs. It has data starting from January 2011. Adelaide Metro started providing this data publicly in November 2010.
Copyright 2011 Michael Farrell http://micolous.id.au
This program is free software. It comes without any warranty, to the extent permitted by applicable law. You can redistribute it and/or modify it under the terms of the Do What The Fuck You Want To Public License, Version 2, as published by Sam Hocevar. See http://sam.zoy.org/wtfpl/COPYING for more details.
The data provided (in the gtfs folder) is licensed under Creative Commons
Australia Attribution 3.0
License.
A current version of the data held in this repository is available for free from Adelaide Metro's website, at http://www.adelaidemetro.com.au/Developer-Information.