Thanks to Keith Wright for diligently testing it and pointing out bugs for me – fixed some issues in the gpio command, and while I was at it, I added in 2 new functions to it to allow for easy exporting/unexporting of the /sys/class/gpio interface – so now you can write a little script to do the exports for you, then run your own program that uses that interface (e.g.) a Python, shell, or php script, then un-export them afterwards, all without needing to be root (or use the sudo command)