Seeking feedback on QA tool: phpflip

I've put together a shell script that I hope will be helpful to others in testing PHP scripts against different PHP builds. It's called 'phpflip', and the source for the script is available here: http://www.killersoft.com/projects/workbench/browser/shell/phpflip My intent is to enable easy switching between not just major versions, such as PHP 4 and PHP 5, but incremental versions -- switch between PHP 4.3.11, 4.4.0, 5.0.5, 5.1.0, and whatever the latest snapshot is with one command. Download PHP distributions, configure and build them, but don't install them -- use phpflip instead. Since each build has the same prefix of /usr (or whatever you specify), they'd all use the same PEAR installation. I'm interested in feedback on this script, particularly from this group -- I intend to release on pearified.com after I've gathered some feedback. (Just assuming it wouldn't be very welcome on PEAR, since it's not actually a PHP script itself.) Thanks, Clay -- Killersoft.com