Enable Slots on Boot

Folks, I have a BBB and would like to enable the slots automatically at boot. If I use the following command from http://hipstercircuits.com/category/beaglebone/page/2/ in a terminal, it works fine, but when I tried to add it to a file and automatically startup the slots driver, no luck.

I created a file named ‘enable_slots.sh’ and added a startup entry pointing to the file.

echo cape-bone-iio > /sys/devices/bone_capemgr.*/slots

Any suggestions? Should I have the startup entry call a terminal window to run this?

Thanks, David