Well after accidently updating my ICAEW dev machine to El Capitan, it broke all of my local paths and I could no longer use grunt to build my work files.
D'OH!
After much blood, sweat and tears, thinking I had broken my machine, I decided that I was determind to have faith in Mac and fix issue rather than rolling back my operating system to Yosemite.
So I set out on a quest to fix my machine...
Turns out it wasn't as difficult as I thought, I could under stand why I kept getting error when trying to install new gems onto my machine, I simply got:
ERROR: While executing gem ... (Errno::EPERM) Operation not permitted
It turns out Apparently with OSX el Capitan, there is a new security function that prevents you from modifying system files called Rootless
If you install gems on /usr/local/bin there will be no problem because rootless doesn't affect this path.
So all you need to do is add the below to overide the problem:
-n /usr/local/bin
sudo gem install -n /usr/local/bin compass --version versionnumber
sudo gem uninstall -n /usr/local/bin compass --version versionnumber